1This is Info file autoconf.info, produced by Makeinfo version 1.67 from 2the input file /home/bje/autoconf-2.13/autoconf.texi. 3 4START-INFO-DIR-ENTRY 5* Autoconf: (autoconf). Create source code configuration scripts. 6END-INFO-DIR-ENTRY 7 8 Autoconf: Creating Automatic Configuration Scripts, by David 9MacKenzie. 10 11 This file documents the GNU Autoconf package for creating scripts to 12configure source code packages using templates and an `m4' macro 13package. 14 15 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998 Free Software 16Foundation, Inc. 17 18 Permission is granted to make and distribute verbatim copies of this 19manual provided the copyright notice and this permission notice are 20preserved on all copies. 21 22 Permission is granted to copy and distribute modified versions of 23this manual under the conditions for verbatim copying, provided that 24the entire resulting derived work is distributed under the terms of a 25permission notice identical to this one. 26 27 Permission is granted to copy and distribute translations of this 28manual into another language, under the above conditions for modified 29versions, except that this permission notice may be stated in a 30translation approved by the Foundation. 31 32 33File: autoconf.info, Node: Top, Next: Introduction, Prev: (dir), Up: (dir) 34 35 This file documents the GNU Autoconf package for creating scripts to 36configure source code packages using templates and an `m4' macro 37package. This is edition 2.13, for Autoconf version 2.13. 38 39* Menu: 40 41* Introduction:: Autoconf's purpose, strengths, and weaknesses. 42* Making configure Scripts:: How to organize and produce Autoconf scripts. 43* Setup:: Initialization and output. 44* Existing Tests:: Macros that check for particular features. 45* Writing Tests:: How to write new feature checks. 46* Results:: What to do with results from feature checks. 47* Writing Macros:: Adding new macros to Autoconf. 48* Manual Configuration:: Selecting features that can't be guessed. 49* Site Configuration:: Local defaults for `configure'. 50* Invoking configure:: How to use the Autoconf output. 51* Invoking config.status:: Recreating a configuration. 52* Questions:: Questions about Autoconf, with answers. 53* Upgrading:: Tips for upgrading from version 1. 54* History:: History of Autoconf. 55* Old Macro Names:: Backward compatibility macros. 56* Environment Variable Index:: Index of environment variables used. 57* Output Variable Index:: Index of variables set in output files. 58* Preprocessor Symbol Index:: Index of C preprocessor symbols defined. 59* Macro Index:: Index of Autoconf macros. 60 61 -- The Detailed Node Listing -- 62 63Making `configure' Scripts 64 65* Writing configure.in:: What to put in an Autoconf input file. 66* Invoking autoscan:: Semi-automatic `configure.in' writing. 67* Invoking ifnames:: Listing the conditionals in source code. 68* Invoking autoconf:: How to create configuration scripts. 69* Invoking autoreconf:: Remaking multiple `configure' scripts. 70 71Initialization and Output Files 72 73* Input:: Where Autoconf should find files. 74* Output:: Creating output files. 75* Makefile Substitutions:: Using output variables in `Makefile's. 76* Configuration Headers:: Creating a configuration header file. 77* Subdirectories:: Configuring independent packages together. 78* Default Prefix:: Changing the default installation prefix. 79* Versions:: Version numbers in `configure'. 80 81Substitutions in Makefiles 82 83* Preset Output Variables:: Output variables that are always set. 84* Build Directories:: Supporting multiple concurrent compiles. 85* Automatic Remaking:: Makefile rules for configuring. 86 87Configuration Header Files 88 89* Header Templates:: Input for the configuration headers. 90* Invoking autoheader:: How to create configuration templates. 91 92Existing Tests 93 94* Alternative Programs:: Selecting between alternative programs. 95* Libraries:: Library archives that might be missing. 96* Library Functions:: C library functions that might be missing. 97* Header Files:: Header files that might be missing. 98* Structures:: Structures or members that might be missing. 99* Typedefs:: `typedef's that might be missing. 100* C Compiler Characteristics:: 101* Fortran 77 Compiler Characteristics:: 102* System Services:: Operating system services. 103* UNIX Variants:: Special kludges for specific UNIX variants. 104 105Alternative Programs 106 107* Particular Programs:: Special handling to find certain programs. 108* Generic Programs:: How to find other programs. 109 110Library Functions 111 112* Particular Functions:: Special handling to find certain functions. 113* Generic Functions:: How to find other functions. 114 115Header Files 116 117* Particular Headers:: Special handling to find certain headers. 118* Generic Headers:: How to find other headers. 119 120Typedefs 121 122* Particular Typedefs:: Special handling to find certain types. 123* Generic Typedefs:: How to find other types. 124 125Writing Tests 126 127* Examining Declarations:: Detecting header files and declarations. 128* Examining Syntax:: Detecting language syntax features. 129* Examining Libraries:: Detecting functions and global variables. 130* Run Time:: Testing for run-time features. 131* Portable Shell:: Shell script portability pitfalls. 132* Testing Values and Files:: Checking strings and files. 133* Multiple Cases:: Tests for several possible values. 134* Language Choice:: Selecting which language to use for testing. 135 136Checking Run Time Behavior 137 138* Test Programs:: Running test programs. 139* Guidelines:: General rules for writing test programs. 140* Test Functions:: Avoiding pitfalls in test programs. 141 142Results of Tests 143 144* Defining Symbols:: Defining C preprocessor symbols. 145* Setting Output Variables:: Replacing variables in output files. 146* Caching Results:: Speeding up subsequent `configure' runs. 147* Printing Messages:: Notifying users of progress or problems. 148 149Caching Results 150 151* Cache Variable Names:: Shell variables used in caches. 152* Cache Files:: Files `configure' uses for caching. 153 154Writing Macros 155 156* Macro Definitions:: Basic format of an Autoconf macro. 157* Macro Names:: What to call your new macros. 158* Quoting:: Protecting macros from unwanted expansion. 159* Dependencies Between Macros:: What to do when macros depend on other macros. 160 161Dependencies Between Macros 162 163* Prerequisite Macros:: Ensuring required information. 164* Suggested Ordering:: Warning about possible ordering problems. 165* Obsolete Macros:: Warning about old ways of doing things. 166 167Manual Configuration 168 169* Specifying Names:: Specifying the system type. 170* Canonicalizing:: Getting the canonical system type. 171* System Type Variables:: Variables containing the system type. 172* Using System Type:: What to do with the system type. 173 174Site Configuration 175 176* External Software:: Working with other optional software. 177* Package Options:: Selecting optional features. 178* Site Details:: Configuring site details. 179* Transforming Names:: Changing program names when installing. 180* Site Defaults:: Giving `configure' local defaults. 181 182Transforming Program Names When Installing 183 184* Transformation Options:: `configure' options to transform names. 185* Transformation Examples:: Sample uses of transforming names. 186* Transformation Rules:: `Makefile' uses of transforming names. 187 188Running `configure' Scripts 189 190* Basic Installation:: Instructions for typical cases. 191* Compilers and Options:: Selecting compilers and optimization. 192* Multiple Architectures:: Compiling for multiple architectures at once. 193* Installation Names:: Installing in different directories. 194* Optional Features:: Selecting optional features. 195* System Type:: Specifying the system type. 196* Sharing Defaults:: Setting site-wide defaults for `configure'. 197* Operation Controls:: Changing how `configure' runs. 198 199Questions About Autoconf 200 201* Distributing:: Distributing `configure' scripts. 202* Why GNU m4:: Why not use the standard `m4'? 203* Bootstrapping:: Autoconf and GNU `m4' require each other? 204* Why Not Imake:: Why GNU uses `configure' instead of Imake. 205 206Upgrading From Version 1 207 208* Changed File Names:: Files you might rename. 209* Changed Makefiles:: New things to put in `Makefile.in'. 210* Changed Macros:: Macro calls you might replace. 211* Invoking autoupdate:: Replacing old macro names in `configure.in'. 212* Changed Results:: Changes in how to check test results. 213* Changed Macro Writing:: Better ways to write your own macros. 214 215History of Autoconf 216 217* Genesis:: Prehistory and naming of `configure'. 218* Exodus:: The plagues of `m4' and Perl. 219* Leviticus:: The priestly code of portability arrives. 220* Numbers:: Growth and contributors. 221* Deuteronomy:: Approaching the promises of easy configuration. 222 223 224File: autoconf.info, Node: Introduction, Next: Making configure Scripts, Prev: Top, Up: Top 225 226Introduction 227************ 228 229 A physicist, an engineer, and a computer scientist were 230 discussing the nature of God. Surely a Physicist, said the 231 physicist, because early in the Creation, God made Light; and you 232 know, Maxwell's equations, the dual nature of electro-magnetic 233 waves, the relativist consequences... An Engineer!, said the 234 engineer, because before making Light, God split the Chaos into 235 Land and Water; it takes a hell of an engineer to handle that big 236 amount of mud, and orderly separation of solids from 237 liquids... The computer scientist shouted: And the Chaos, 238 where do you think it was coming from, hmm? 239 240 ---Anonymous 241 242 Autoconf is a tool for producing shell scripts that automatically 243configure software source code packages to adapt to many kinds of 244UNIX-like systems. The configuration scripts produced by Autoconf are 245independent of Autoconf when they are run, so their users do not need to 246have Autoconf. 247 248 The configuration scripts produced by Autoconf require no manual user 249intervention when run; they do not normally even need an argument 250specifying the system type. Instead, they test for the presence of each 251feature that the software package they are for might need individually. 252(Before each check, they print a one-line message stating what they are 253checking for, so the user doesn't get too bored while waiting for the 254script to finish.) As a result, they deal well with systems that are 255hybrids or customized from the more common UNIX variants. There is no 256need to maintain files that list the features supported by each release 257of each variant of UNIX. 258 259 For each software package that Autoconf is used with, it creates a 260configuration script from a template file that lists the system 261features that the package needs or can use. After the shell code to 262recognize and respond to a system feature has been written, Autoconf 263allows it to be shared by many software packages that can use (or need) 264that feature. If it later turns out that the shell code needs 265adjustment for some reason, it needs to be changed in only one place; 266all of the configuration scripts can be regenerated automatically to 267take advantage of the updated code. 268 269 The Metaconfig package is similar in purpose to Autoconf, but the 270scripts it produces require manual user intervention, which is quite 271inconvenient when configuring large source trees. Unlike Metaconfig 272scripts, Autoconf scripts can support cross-compiling, if some care is 273taken in writing them. 274 275 There are several jobs related to making portable software packages 276that Autoconf currently does not do. Among these are automatically 277creating `Makefile' files with all of the standard targets, and 278supplying replacements for standard library functions and header files 279on systems that lack them. Work is in progress to add those features in 280the future. 281 282 Autoconf imposes some restrictions on the names of macros used with 283`#ifdef' in C programs (*note Preprocessor Symbol Index::.). 284 285 Autoconf requires GNU `m4' in order to generate the scripts. It 286uses features that some UNIX versions of `m4' do not have. It also 287overflows internal limits of some versions of `m4', including GNU `m4' 2881.0. You must use version 1.1 or later of GNU `m4'. Using version 1.3 289or later will be much faster than 1.1 or 1.2. 290 291 *Note Upgrading::, for information about upgrading from version 1. 292*Note History::, for the story of Autoconf's development. *Note 293Questions::, for answers to some common questions about Autoconf. 294 295 Mail suggestions and bug reports for Autoconf to 296`bug-gnu-utils@prep.ai.mit.edu'. Please include the Autoconf version 297number, which you can get by running `autoconf --version'. 298 299 300File: autoconf.info, Node: Making configure Scripts, Next: Setup, Prev: Introduction, Up: Top 301 302Making `configure' Scripts 303************************** 304 305 The configuration scripts that Autoconf produces are by convention 306called `configure'. When run, `configure' creates several files, 307replacing configuration parameters in them with appropriate values. 308The files that `configure' creates are: 309 310 * one or more `Makefile' files, one in each subdirectory of the 311 package (*note Makefile Substitutions::.); 312 313 * optionally, a C header file, the name of which is configurable, 314 containing `#define' directives (*note Configuration Headers::.); 315 316 * a shell script called `config.status' that, when run, will recreate 317 the files listed above (*note Invoking config.status::.); 318 319 * a shell script called `config.cache' that saves the results of 320 running many of the tests (*note Cache Files::.); 321 322 * a file called `config.log' containing any messages produced by 323 compilers, to help debugging if `configure' makes a mistake. 324 325 To create a `configure' script with Autoconf, you need to write an 326Autoconf input file `configure.in' and run `autoconf' on it. If you 327write your own feature tests to supplement those that come with 328Autoconf, you might also write files called `aclocal.m4' and 329`acsite.m4'. If you use a C header file to contain `#define' 330directives, you might also write `acconfig.h', and you will distribute 331the Autoconf-generated file `config.h.in' with the package. 332 333 Here is a diagram showing how the files that can be used in 334configuration are produced. Programs that are executed are suffixed by 335`*'. Optional files are enclosed in square brackets (`[]'). 336`autoconf' and `autoheader' also read the installed Autoconf macro 337files (by reading `autoconf.m4'). 338 339Files used in preparing a software package for distribution: 340 your source files --> [autoscan*] --> [configure.scan] --> configure.in 341 342 configure.in --. .------> autoconf* -----> configure 343 +---+ 344 [aclocal.m4] --+ `---. 345 [acsite.m4] ---' | 346 +--> [autoheader*] -> [config.h.in] 347 [acconfig.h] ----. | 348 +-----' 349 [config.h.top] --+ 350 [config.h.bot] --' 351 352 Makefile.in -------------------------------> Makefile.in 353 354Files used in configuring a software package: 355 .-------------> config.cache 356 configure* ------------+-------------> config.log 357 | 358 [config.h.in] -. v .-> [config.h] -. 359 +--> config.status* -+ +--> make* 360 Makefile.in ---' `-> Makefile ---' 361 362* Menu: 363 364* Writing configure.in:: What to put in an Autoconf input file. 365* Invoking autoscan:: Semi-automatic `configure.in' writing. 366* Invoking ifnames:: Listing the conditionals in source code. 367* Invoking autoconf:: How to create configuration scripts. 368* Invoking autoreconf:: Remaking multiple `configure' scripts. 369 370 371File: autoconf.info, Node: Writing configure.in, Next: Invoking autoscan, Prev: Making configure Scripts, Up: Making configure Scripts 372 373Writing `configure.in' 374====================== 375 376 To produce a `configure' script for a software package, create a 377file called `configure.in' that contains invocations of the Autoconf 378macros that test the system features your package needs or can use. 379Autoconf macros already exist to check for many features; see *Note 380Existing Tests::, for their descriptions. For most other features, you 381can use Autoconf template macros to produce custom checks; see *Note 382Writing Tests::, for information about them. For especially tricky or 383specialized features, `configure.in' might need to contain some 384hand-crafted shell commands. The `autoscan' program can give you a 385good start in writing `configure.in' (*note Invoking autoscan::., for 386more information). 387 388 The order in which `configure.in' calls the Autoconf macros is not 389important, with a few exceptions. Every `configure.in' must contain a 390call to `AC_INIT' before the checks, and a call to `AC_OUTPUT' at the 391end (*note Output::.). Additionally, some macros rely on other macros 392having been called first, because they check previously set values of 393some variables to decide what to do. These macros are noted in the 394individual descriptions (*note Existing Tests::.), and they also warn 395you when creating `configure' if they are called out of order. 396 397 To encourage consistency, here is a suggested order for calling the 398Autoconf macros. Generally speaking, the things near the end of this 399list could depend on things earlier in it. For example, library 400functions could be affected by typedefs and libraries. 401 402 `AC_INIT(FILE)' 403 checks for programs 404 checks for libraries 405 checks for header files 406 checks for typedefs 407 checks for structures 408 checks for compiler characteristics 409 checks for library functions 410 checks for system services 411 `AC_OUTPUT([FILE...])' 412 413 It is best to put each macro call on its own line in `configure.in'. 414Most of the macros don't add extra newlines; they rely on the newline 415after the macro call to terminate the commands. This approach makes 416the generated `configure' script a little easier to read by not 417inserting lots of blank lines. It is generally safe to set shell 418variables on the same line as a macro call, because the shell allows 419assignments without intervening newlines. 420 421 When calling macros that take arguments, there must not be any blank 422space between the macro name and the open parenthesis. Arguments can be 423more than one line long if they are enclosed within the `m4' quote 424characters `[' and `]'. If you have a long line such as a list of file 425names, you can generally use a backslash at the end of a line to 426continue it logically on the next line (this is implemented by the 427shell, not by anything special that Autoconf does). 428 429 Some macros handle two cases: what to do if the given condition is 430met, and what to do if the condition is not met. In some places you 431might want to do something if a condition is true but do nothing if it's 432false, or vice versa. To omit the true case, pass an empty value for 433the ACTION-IF-FOUND argument to the macro. To omit the false case, 434omit the ACTION-IF-NOT-FOUND argument to the macro, including the comma 435before it. 436 437 You can include comments in `configure.in' files by starting them 438with the `m4' builtin macro `dnl', which discards text up through the 439next newline. These comments do not appear in the generated 440`configure' scripts. For example, it is helpful to begin 441`configure.in' files with a line like this: 442 443 dnl Process this file with autoconf to produce a configure script. 444 445 446File: autoconf.info, Node: Invoking autoscan, Next: Invoking ifnames, Prev: Writing configure.in, Up: Making configure Scripts 447 448Using `autoscan' to Create `configure.in' 449========================================= 450 451 The `autoscan' program can help you create a `configure.in' file for 452a software package. `autoscan' examines source files in the directory 453tree rooted at a directory given as a command line argument, or the 454current directory if none is given. It searches the source files for 455common portability problems and creates a file `configure.scan' which 456is a preliminary `configure.in' for that package. 457 458 You should manually examine `configure.scan' before renaming it to 459`configure.in'; it will probably need some adjustments. Occasionally 460`autoscan' outputs a macro in the wrong order relative to another 461macro, so that `autoconf' produces a warning; you need to move such 462macros manually. Also, if you want the package to use a configuration 463header file, you must add a call to `AC_CONFIG_HEADER' (*note 464Configuration Headers::.). You might also have to change or add some 465`#if' directives to your program in order to make it work with Autoconf 466(*note Invoking ifnames::., for information about a program that can 467help with that job). 468 469 `autoscan' uses several data files, which are installed along with 470the distributed Autoconf macro files, to determine which macros to 471output when it finds particular symbols in a package's source files. 472These files all have the same format. Each line consists of a symbol, 473whitespace, and the Autoconf macro to output if that symbol is 474encountered. Lines starting with `#' are comments. 475 476 `autoscan' is only installed if you already have Perl installed. 477`autoscan' accepts the following options: 478 479`--help' 480 Print a summary of the command line options and exit. 481 482`--macrodir=DIR' 483 Look for the data files in directory DIR instead of the default 484 installation directory. You can also set the `AC_MACRODIR' 485 environment variable to a directory; this option overrides the 486 environment variable. 487 488`--verbose' 489 Print the names of the files it examines and the potentially 490 interesting symbols it finds in them. This output can be 491 voluminous. 492 493`--version' 494 Print the version number of Autoconf and exit. 495 496 497File: autoconf.info, Node: Invoking ifnames, Next: Invoking autoconf, Prev: Invoking autoscan, Up: Making configure Scripts 498 499Using `ifnames' to List Conditionals 500==================================== 501 502 `ifnames' can help when writing a `configure.in' for a software 503package. It prints the identifiers that the package already uses in C 504preprocessor conditionals. If a package has already been set up to 505have some portability, this program can help you figure out what its 506`configure' needs to check for. It may help fill in some gaps in a 507`configure.in' generated by `autoscan' (*note Invoking autoscan::.). 508 509 `ifnames' scans all of the C source files named on the command line 510(or the standard input, if none are given) and writes to the standard 511output a sorted list of all the identifiers that appear in those files 512in `#if', `#elif', `#ifdef', or `#ifndef' directives. It prints each 513identifier on a line, followed by a space-separated list of the files 514in which that identifier occurs. 515 516`ifnames' accepts the following options: 517 518`--help' 519`-h' 520 Print a summary of the command line options and exit. 521 522`--macrodir=DIR' 523`-m DIR' 524 Look for the Autoconf macro files in directory DIR instead of the 525 default installation directory. Only used to get the version 526 number. You can also set the `AC_MACRODIR' environment variable 527 to a directory; this option overrides the environment variable. 528 529`--version' 530 Print the version number of Autoconf and exit. 531 532 533File: autoconf.info, Node: Invoking autoconf, Next: Invoking autoreconf, Prev: Invoking ifnames, Up: Making configure Scripts 534 535Using `autoconf' to Create `configure' 536====================================== 537 538 To create `configure' from `configure.in', run the `autoconf' 539program with no arguments. `autoconf' processes `configure.in' with 540the `m4' macro processor, using the Autoconf macros. If you give 541`autoconf' an argument, it reads that file instead of `configure.in' 542and writes the configuration script to the standard output instead of 543to `configure'. If you give `autoconf' the argument `-', it reads the 544standard input instead of `configure.in' and writes the configuration 545script on the standard output. 546 547 The Autoconf macros are defined in several files. Some of the files 548are distributed with Autoconf; `autoconf' reads them first. Then it 549looks for the optional file `acsite.m4' in the directory that contains 550the distributed Autoconf macro files, and for the optional file 551`aclocal.m4' in the current directory. Those files can contain your 552site's or the package's own Autoconf macro definitions (*note Writing 553Macros::., for more information). If a macro is defined in more than 554one of the files that `autoconf' reads, the last definition it reads 555overrides the earlier ones. 556 557 `autoconf' accepts the following options: 558 559`--help' 560`-h' 561 Print a summary of the command line options and exit. 562 563`--localdir=DIR' 564`-l DIR' 565 Look for the package file `aclocal.m4' in directory DIR instead of 566 in the current directory. 567 568`--macrodir=DIR' 569`-m DIR' 570 Look for the installed macro files in directory DIR. You can also 571 set the `AC_MACRODIR' environment variable to a directory; this 572 option overrides the environment variable. 573 574`--version' 575 Print the version number of Autoconf and exit. 576 577 578File: autoconf.info, Node: Invoking autoreconf, Prev: Invoking autoconf, Up: Making configure Scripts 579 580Using `autoreconf' to Update `configure' Scripts 581================================================ 582 583 If you have a lot of Autoconf-generated `configure' scripts, the 584`autoreconf' program can save you some work. It runs `autoconf' (and 585`autoheader', where appropriate) repeatedly to remake the Autoconf 586`configure' scripts and configuration header templates in the directory 587tree rooted at the current directory. By default, it only remakes 588those files that are older than their `configure.in' or (if present) 589`aclocal.m4'. Since `autoheader' does not change the timestamp of its 590output file if the file wouldn't be changing, this is not necessarily 591the minimum amount of work. If you install a new version of Autoconf, 592you can make `autoreconf' remake *all* of the files by giving it the 593`--force' option. 594 595 If you give `autoreconf' the `--macrodir=DIR' or `--localdir=DIR' 596options, it passes them down to `autoconf' and `autoheader' (with 597relative paths adjusted properly). 598 599 `autoreconf' does not support having, in the same directory tree, 600both directories that are parts of a larger package (sharing 601`aclocal.m4' and `acconfig.h'), and directories that are independent 602packages (each with their own `aclocal.m4' and `acconfig.h'). It 603assumes that they are all part of the same package, if you use 604`--localdir', or that each directory is a separate package, if you 605don't use it. This restriction may be removed in the future. 606 607 *Note Automatic Remaking::, for `Makefile' rules to automatically 608remake `configure' scripts when their source files change. That method 609handles the timestamps of configuration header templates properly, but 610does not pass `--macrodir=DIR' or `--localdir=DIR'. 611 612`autoreconf' accepts the following options: 613 614`--help' 615`-h' 616 Print a summary of the command line options and exit. 617 618`--force' 619`-f' 620 Remake even `configure' scripts and configuration headers that are 621 newer than their input files (`configure.in' and, if present, 622 `aclocal.m4'). 623 624`--localdir=DIR' 625`-l DIR' 626 Have `autoconf' and `autoheader' look for the package files 627 `aclocal.m4' and (`autoheader' only) `acconfig.h' (but not 628 `FILE.top' and `FILE.bot') in directory DIR instead of in the 629 directory containing each `configure.in'. 630 631`--macrodir=DIR' 632`-m DIR' 633 Look for the Autoconf macro files in directory DIR instead of the 634 default installation directory. You can also set the `AC_MACRODIR' 635 environment variable to a directory; this option overrides the 636 environment variable. 637 638`--verbose' 639 Print the name of each directory where `autoreconf' runs 640 `autoconf' (and `autoheader', if appropriate). 641 642`--version' 643 Print the version number of Autoconf and exit. 644 645 646File: autoconf.info, Node: Setup, Next: Existing Tests, Prev: Making configure Scripts, Up: Top 647 648Initialization and Output Files 649******************************* 650 651 Autoconf-generated `configure' scripts need some information about 652how to initialize, such as how to find the package's source files; and 653about the output files to produce. The following sections describe 654initialization and creating output files. 655 656* Menu: 657 658* Input:: Where Autoconf should find files. 659* Output:: Creating output files. 660* Makefile Substitutions:: Using output variables in `Makefile's. 661* Configuration Headers:: Creating a configuration header file. 662* Subdirectories:: Configuring independent packages together. 663* Default Prefix:: Changing the default installation prefix. 664* Versions:: Version numbers in `configure'. 665 666 667File: autoconf.info, Node: Input, Next: Output, Prev: Setup, Up: Setup 668 669Finding `configure' Input 670========================= 671 672 Every `configure' script must call `AC_INIT' before doing anything 673else. The only other required macro is `AC_OUTPUT' (*note Output::.). 674 675 - Macro: AC_INIT (UNIQUE-FILE-IN-SOURCE-DIR) 676 Process any command-line arguments and find the source code 677 directory. UNIQUE-FILE-IN-SOURCE-DIR is some file that is in the 678 package's source directory; `configure' checks for this file's 679 existence to make sure that the directory that it is told contains 680 the source code in fact does. Occasionally people accidentally 681 specify the wrong directory with `--srcdir'; this is a safety 682 check. *Note Invoking configure::, for more information. 683 684 Packages that do manual configuration or use the `install' program 685might need to tell `configure' where to find some other shell scripts 686by calling `AC_CONFIG_AUX_DIR', though the default places it looks are 687correct for most cases. 688 689 - Macro: AC_CONFIG_AUX_DIR(DIR) 690 Use the `install-sh', `config.sub', `config.guess', and Cygnus 691 `configure' scripts that are in directory DIR. These are 692 auxiliary files used in configuration. DIR can be either absolute 693 or relative to `SRCDIR'. The default is `SRCDIR' or `SRCDIR/..' or 694 `SRCDIR/../..', whichever is the first that contains `install-sh'. 695 The other files are not checked for, so that using 696 `AC_PROG_INSTALL' does not automatically require distributing the 697 other auxiliary files. It checks for `install.sh' also, but that 698 name is obsolete because some `make' programs have a rule that 699 creates `install' from it if there is no `Makefile'. 700 701 702File: autoconf.info, Node: Output, Next: Makefile Substitutions, Prev: Input, Up: Setup 703 704Creating Output Files 705===================== 706 707 Every Autoconf-generated `configure' script must finish by calling 708`AC_OUTPUT'. It is the macro that creates the `Makefile's and optional 709other files resulting from configuration. The only other required 710macro is `AC_INIT' (*note Input::.). 711 712 - Macro: AC_OUTPUT ([FILE... [, EXTRA-CMDS [, INIT-CMDS]]]) 713 Create output files. Call this macro once, at the end of 714 `configure.in'. The FILE... argument is a whitespace-separated 715 list of output files; it may be empty. This macro creates each 716 file `FILE' by copying an input file (by default named `FILE.in'), 717 substituting the output variable values. *Note Makefile 718 Substitutions::, for more information on using output variables. 719 *Note Setting Output Variables::, for more information on creating 720 them. This macro creates the directory that the file is in if it 721 doesn't exist (but not the parents of that directory). Usually, 722 `Makefile's are created this way, but other files, such as 723 `.gdbinit', can be specified as well. 724 725 If `AC_CONFIG_HEADER', `AC_LINK_FILES', or `AC_CONFIG_SUBDIRS' has 726 been called, this macro also creates the files named as their 727 arguments. 728 729 A typical call to `AC_OUTPUT' looks like this: 730 AC_OUTPUT(Makefile src/Makefile man/Makefile X/Imakefile) 731 732 You can override an input file name by appending to FILE a 733 colon-separated list of input files. Examples: 734 AC_OUTPUT(Makefile:templates/top.mk lib/Makefile:templates/lib.mk) 735 AC_OUTPUT(Makefile:templates/vars.mk:Makefile.in:templates/rules.mk) 736 Doing this allows you to keep your file names acceptable to 737 MS-DOS, or to prepend and/or append boilerplate to the file. 738 739 If you pass EXTRA-CMDS, those commands will be inserted into 740 `config.status' to be run after all its other processing. If 741 INIT-CMDS are given, they are inserted just before EXTRA-CMDS, 742 with shell variable, command, and backslash substitutions 743 performed on them in `configure'. You can use INIT-CMDS to pass 744 variables from `configure' to the EXTRA-CMDS. If 745 `AC_OUTPUT_COMMANDS' has been called, the commands given to it are 746 run just before the commands passed to this macro. 747 748 - Macro: AC_OUTPUT_COMMANDS (EXTRA-CMDS [, INIT-CMDS]) 749 Specify additional shell commands to run at the end of 750 `config.status', and shell commands to initialize any variables 751 from `configure'. This macro may be called multiple times. Here 752 is an unrealistic example: 753 754 fubar=27 755 AC_OUTPUT_COMMANDS([echo this is extra $fubar, and so on.], fubar=$fubar) 756 AC_OUTPUT_COMMANDS([echo this is another, extra, bit], [echo init bit]) 757 758 If you run `make' on subdirectories, you should run it using the 759`make' variable `MAKE'. Most versions of `make' set `MAKE' to the name 760of the `make' program plus any options it was given. (But many do not 761include in it the values of any variables set on the command line, so 762those are not passed on automatically.) Some old versions of `make' do 763not set this variable. The following macro allows you to use it even 764with those versions. 765 766 - Macro: AC_PROG_MAKE_SET 767 If `make' predefines the variable `MAKE', define output variable 768 `SET_MAKE' to be empty. Otherwise, define `SET_MAKE' to contain 769 `MAKE=make'. Calls `AC_SUBST' for `SET_MAKE'. 770 771 To use this macro, place a line like this in each `Makefile.in' that 772runs `MAKE' on other directories: 773 774 @SET_MAKE@ 775 776 777File: autoconf.info, Node: Makefile Substitutions, Next: Configuration Headers, Prev: Output, Up: Setup 778 779Substitutions in Makefiles 780========================== 781 782 Each subdirectory in a distribution that contains something to be 783compiled or installed should come with a file `Makefile.in', from which 784`configure' will create a `Makefile' in that directory. To create a 785`Makefile', `configure' performs a simple variable substitution, 786replacing occurrences of `@VARIABLE@' in `Makefile.in' with the value 787that `configure' has determined for that variable. Variables that are 788substituted into output files in this way are called "output 789variables". They are ordinary shell variables that are set in 790`configure'. To make `configure' substitute a particular variable into 791the output files, the macro `AC_SUBST' must be called with that 792variable name as an argument. Any occurrences of `@VARIABLE@' for 793other variables are left unchanged. *Note Setting Output Variables::, 794for more information on creating output variables with `AC_SUBST'. 795 796 A software package that uses a `configure' script should be 797distributed with a file `Makefile.in', but no `Makefile'; that way, the 798user has to properly configure the package for the local system before 799compiling it. 800 801 *Note Makefile Conventions: (standards)Makefile Conventions, for 802more information on what to put in `Makefile's. 803 804* Menu: 805 806* Preset Output Variables:: Output variables that are always set. 807* Build Directories:: Supporting multiple concurrent compiles. 808* Automatic Remaking:: Makefile rules for configuring. 809 810 811File: autoconf.info, Node: Preset Output Variables, Next: Build Directories, Prev: Makefile Substitutions, Up: Makefile Substitutions 812 813Preset Output Variables 814----------------------- 815 816 Some output variables are preset by the Autoconf macros. Some of the 817Autoconf macros set additional output variables, which are mentioned in 818the descriptions for those macros. *Note Output Variable Index::, for a 819complete list of output variables. Here is what each of the preset ones 820contains. *Note Variables for Installation Directories: 821(standards)Directory Variables, for more information about the 822variables with names that end in `dir'. 823 824 - Variable: bindir 825 The directory for installing executables that users run. 826 827 - Variable: configure_input 828 A comment saying that the file was generated automatically by 829 `configure' and giving the name of the input file. `AC_OUTPUT' 830 adds a comment line containing this variable to the top of every 831 `Makefile' it creates. For other files, you should reference this 832 variable in a comment at the top of each input file. For example, 833 an input shell script should begin like this: 834 835 #! /bin/sh 836 # @configure_input@ 837 838 The presence of that line also reminds people editing the file 839 that it needs to be processed by `configure' in order to be used. 840 841 - Variable: datadir 842 The directory for installing read-only architecture-independent 843 data. 844 845 - Variable: exec_prefix 846 The installation prefix for architecture-dependent files. 847 848 - Variable: includedir 849 The directory for installing C header files. 850 851 - Variable: infodir 852 The directory for installing documentation in Info format. 853 854 - Variable: libdir 855 The directory for installing object code libraries. 856 857 - Variable: libexecdir 858 The directory for installing executables that other programs run. 859 860 - Variable: localstatedir 861 The directory for installing modifiable single-machine data. 862 863 - Variable: mandir 864 The top-level directory for installing documentation in man format. 865 866 - Variable: oldincludedir 867 The directory for installing C header files for non-gcc compilers. 868 869 - Variable: prefix 870 The installation prefix for architecture-independent files. 871 872 - Variable: sbindir 873 The directory for installing executables that system 874 administrators run. 875 876 - Variable: sharedstatedir 877 The directory for installing modifiable architecture-independent 878 data. 879 880 - Variable: srcdir 881 The directory that contains the source code for that `Makefile'. 882 883 - Variable: sysconfdir 884 The directory for installing read-only single-machine data. 885 886 - Variable: top_srcdir 887 The top-level source code directory for the package. In the 888 top-level directory, this is the same as `srcdir'. 889 890 - Variable: CFLAGS 891 Debugging and optimization options for the C compiler. If it is 892 not set in the environment when `configure' runs, the default 893 value is set when you call `AC_PROG_CC' (or empty if you don't). 894 `configure' uses this variable when compiling programs to test for 895 C features. 896 897 - Variable: CPPFLAGS 898 Header file search directory (`-IDIR') and any other miscellaneous 899 options for the C preprocessor and compiler. If it is not set in 900 the environment when `configure' runs, the default value is empty. 901 `configure' uses this variable when compiling or preprocessing 902 programs to test for C features. 903 904 - Variable: CXXFLAGS 905 Debugging and optimization options for the C++ compiler. If it is 906 not set in the environment when `configure' runs, the default 907 value is set when you call `AC_PROG_CXX' (or empty if you don't). 908 `configure' uses this variable when compiling programs to test for 909 C++ features. 910 911 - Variable: FFLAGS 912 Debugging and optimization options for the Fortran 77 compiler. 913 If it is not set in the environment when `configure' runs, the 914 default value is set when you call `AC_PROG_F77' (or empty if you 915 don't). `configure' uses this variable when compiling programs to 916 test for Fortran 77 features. 917 918 - Variable: DEFS 919 `-D' options to pass to the C compiler. If `AC_CONFIG_HEADER' is 920 called, `configure' replaces `@DEFS@' with `-DHAVE_CONFIG_H' 921 instead (*note Configuration Headers::.). This variable is not 922 defined while `configure' is performing its tests, only when 923 creating the output files. *Note Setting Output Variables::, for 924 how to check the results of previous tests. 925 926 - Variable: LDFLAGS 927 Stripping (`-s') and any other miscellaneous options for the 928 linker. If it is not set in the environment when `configure' runs, 929 the default value is empty. `configure' uses this variable when 930 linking programs to test for C features. 931 932 - Variable: LIBS 933 `-l' and `-L' options to pass to the linker. 934 935 936File: autoconf.info, Node: Build Directories, Next: Automatic Remaking, Prev: Preset Output Variables, Up: Makefile Substitutions 937 938Build Directories 939----------------- 940 941 You can support compiling a software package for several 942architectures simultaneously from the same copy of the source code. 943The object files for each architecture are kept in their own directory. 944 945 To support doing this, `make' uses the `VPATH' variable to find the 946files that are in the source directory. GNU `make' and most other 947recent `make' programs can do this. Older `make' programs do not 948support `VPATH'; when using them, the source code must be in the same 949directory as the object files. 950 951 To support `VPATH', each `Makefile.in' should contain two lines that 952look like: 953 954 srcdir = @srcdir@ 955 VPATH = @srcdir@ 956 957 Do not set `VPATH' to the value of another variable, for example 958`VPATH = $(srcdir)', because some versions of `make' do not do variable 959substitutions on the value of `VPATH'. 960 961 `configure' substitutes in the correct value for `srcdir' when it 962produces `Makefile'. 963 964 Do not use the `make' variable `$<', which expands to the pathname 965of the file in the source directory (found with `VPATH'), except in 966implicit rules. (An implicit rule is one such as `.c.o', which tells 967how to create a `.o' file from a `.c' file.) Some versions of `make' 968do not set `$<' in explicit rules; they expand it to an empty value. 969 970 Instead, `Makefile' command lines should always refer to source 971files by prefixing them with `$(srcdir)/'. For example: 972 973 time.info: time.texinfo 974 $(MAKEINFO) $(srcdir)/time.texinfo 975 976 977File: autoconf.info, Node: Automatic Remaking, Prev: Build Directories, Up: Makefile Substitutions 978 979Automatic Remaking 980------------------ 981 982 You can put rules like the following in the top-level `Makefile.in' 983for a package to automatically update the configuration information when 984you change the configuration files. This example includes all of the 985optional files, such as `aclocal.m4' and those related to configuration 986header files. Omit from the `Makefile.in' rules any of these files 987that your package does not use. 988 989 The `${srcdir}/' prefix is included because of limitations in the 990`VPATH' mechanism. 991 992 The `stamp-' files are necessary because the timestamps of 993`config.h.in' and `config.h' will not be changed if remaking them does 994not change their contents. This feature avoids unnecessary 995recompilation. You should include the file `stamp-h.in' your package's 996distribution, so `make' will consider `config.h.in' up to date. On 997some old BSD systems, `touch' or any command that results in an empty 998file does not update the timestamps, so use a command like `echo' as a 999workaround. 1000 1001 ${srcdir}/configure: configure.in aclocal.m4 1002 cd ${srcdir} && autoconf 1003 1004 # autoheader might not change config.h.in, so touch a stamp file. 1005 ${srcdir}/config.h.in: stamp-h.in 1006 ${srcdir}/stamp-h.in: configure.in aclocal.m4 acconfig.h \ 1007 config.h.top config.h.bot 1008 cd ${srcdir} && autoheader 1009 echo timestamp > ${srcdir}/stamp-h.in 1010 1011 config.h: stamp-h 1012 stamp-h: config.h.in config.status 1013 ./config.status 1014 1015 Makefile: Makefile.in config.status 1016 ./config.status 1017 1018 config.status: configure 1019 ./config.status --recheck 1020 1021 In addition, you should pass `echo timestamp > stamp-h' in the 1022EXTRA-CMDS argument to `AC_OUTPUT', so `config.status' will ensure that 1023`config.h' is considered up to date. *Note Output::, for more 1024information about `AC_OUTPUT'. 1025 1026 *Note Invoking config.status::, for more examples of handling 1027configuration-related dependencies. 1028 1029 1030File: autoconf.info, Node: Configuration Headers, Next: Subdirectories, Prev: Makefile Substitutions, Up: Setup 1031 1032Configuration Header Files 1033========================== 1034 1035 When a package tests more than a few C preprocessor symbols, the 1036command lines to pass `-D' options to the compiler can get quite long. 1037This causes two problems. One is that the `make' output is hard to 1038visually scan for errors. More seriously, the command lines can exceed 1039the length limits of some operating systems. As an alternative to 1040passing `-D' options to the compiler, `configure' scripts can create a 1041C header file containing `#define' directives. The `AC_CONFIG_HEADER' 1042macro selects this kind of output. It should be called right after 1043`AC_INIT'. 1044 1045 The package should `#include' the configuration header file before 1046any other header files, to prevent inconsistencies in declarations (for 1047example, if it redefines `const'). Use `#include <config.h>' instead 1048of `#include "config.h"', and pass the C compiler a `-I.' option (or 1049`-I..'; whichever directory contains `config.h'). That way, even if 1050the source directory is configured itself (perhaps to make a 1051distribution), other build directories can also be configured without 1052finding the `config.h' from the source directory. 1053 1054 - Macro: AC_CONFIG_HEADER (HEADER-TO-CREATE ...) 1055 Make `AC_OUTPUT' create the file(s) in the whitespace-separated 1056 list HEADER-TO-CREATE containing C preprocessor `#define' 1057 statements, and replace `@DEFS@' in generated files with 1058 `-DHAVE_CONFIG_H' instead of the value of `DEFS'. The usual name 1059 for HEADER-TO-CREATE is `config.h'. 1060 1061 If HEADER-TO-CREATE already exists and its contents are identical 1062 to what `AC_OUTPUT' would put in it, it is left alone. Doing this 1063 allows some changes in configuration without needlessly causing 1064 object files that depend on the header file to be recompiled. 1065 1066 Usually the input file is named `HEADER-TO-CREATE.in'; however, 1067 you can override the input file name by appending to 1068 HEADER-TO-CREATE, a colon-separated list of input files. Examples: 1069 AC_CONFIG_HEADER(defines.h:defines.hin) 1070 AC_CONFIG_HEADER(defines.h:defs.pre:defines.h.in:defs.post) 1071 1072 Doing this allows you to keep your file names acceptable to 1073 MS-DOS, or to prepend and/or append boilerplate to the file. 1074 1075* Menu: 1076 1077* Header Templates:: Input for the configuration headers. 1078* Invoking autoheader:: How to create configuration templates. 1079 1080 1081File: autoconf.info, Node: Header Templates, Next: Invoking autoheader, Prev: Configuration Headers, Up: Configuration Headers 1082 1083Configuration Header Templates 1084------------------------------ 1085 1086 Your distribution should contain a template file that looks as you 1087want the final header file to look, including comments, with default 1088values in the `#define' statements. For example, suppose your 1089`configure.in' makes these calls: 1090 1091 AC_CONFIG_HEADER(conf.h) 1092 AC_CHECK_HEADERS(unistd.h) 1093 1094Then you could have code like the following in `conf.h.in'. On systems 1095that have `unistd.h', `configure' will change the 0 to a 1. On other 1096systems, it will leave the line unchanged. 1097 1098 /* Define as 1 if you have unistd.h. */ 1099 #define HAVE_UNISTD_H 0 1100 1101 Alternately, if your code tests for configuration options using 1102`#ifdef' instead of `#if', a default value can be to `#undef' the 1103variable instead of to define it to a value. On systems that have 1104`unistd.h', `configure' will change the second line to read `#define 1105HAVE_UNISTD_H 1'. On other systems, it will comment that line out (in 1106case the system predefines that symbol). 1107 1108 /* Define if you have unistd.h. */ 1109 #undef HAVE_UNISTD_H 1110 1111 1112File: autoconf.info, Node: Invoking autoheader, Prev: Header Templates, Up: Configuration Headers 1113 1114Using `autoheader' to Create `config.h.in' 1115------------------------------------------ 1116 1117 The `autoheader' program can create a template file of C `#define' 1118statements for `configure' to use. If `configure.in' invokes 1119`AC_CONFIG_HEADER(FILE)', `autoheader' creates `FILE.in'; if multiple 1120file arguments are given, the first one is used. Otherwise, 1121`autoheader' creates `config.h.in'. 1122 1123 If you give `autoheader' an argument, it uses that file instead of 1124`configure.in' and writes the header file to the standard output 1125instead of to `config.h.in'. If you give `autoheader' an argument of 1126`-', it reads the standard input instead of `configure.in' and writes 1127the header file to the standard output. 1128 1129 `autoheader' scans `configure.in' and figures out which C 1130preprocessor symbols it might define. It copies comments and `#define' 1131and `#undef' statements from a file called `acconfig.h', which comes 1132with and is installed with Autoconf. It also uses a file called 1133`acconfig.h' in the current directory, if present. If you `AC_DEFINE' 1134any additional symbols, you must create that file with entries for 1135them. For symbols defined by `AC_CHECK_HEADERS', `AC_CHECK_FUNCS', 1136`AC_CHECK_SIZEOF', or `AC_CHECK_LIB', `autoheader' generates comments 1137and `#undef' statements itself rather than copying them from a file, 1138since the possible symbols are effectively limitless. 1139 1140 The file that `autoheader' creates contains mainly `#define' and 1141`#undef' statements and their accompanying comments. If `./acconfig.h' 1142contains the string `@TOP@', `autoheader' copies the lines before the 1143line containing `@TOP@' into the top of the file that it generates. 1144Similarly, if `./acconfig.h' contains the string `@BOTTOM@', 1145`autoheader' copies the lines after that line to the end of the file it 1146generates. Either or both of those strings may be omitted. 1147 1148 An alternate way to produce the same effect is to create the files 1149`FILE.top' (typically `config.h.top') and/or `FILE.bot' in the current 1150directory. If they exist, `autoheader' copies them to the beginning 1151and end, respectively, of its output. Their use is discouraged because 1152they have file names that contain two periods, and so can not be stored 1153on MS-DOS; also, they are two more files to clutter up the directory. 1154But if you use the `--localdir=DIR' option to use an `acconfig.h' in 1155another directory, they give you a way to put custom boilerplate in each 1156individual `config.h.in'. 1157 1158 `autoheader' accepts the following options: 1159 1160`--help' 1161`-h' 1162 Print a summary of the command line options and exit. 1163 1164`--localdir=DIR' 1165`-l DIR' 1166 Look for the package files `aclocal.m4' and `acconfig.h' (but not 1167 `FILE.top' and `FILE.bot') in directory DIR instead of in the 1168 current directory. 1169 1170`--macrodir=DIR' 1171`-m DIR' 1172 Look for the installed macro files and `acconfig.h' in directory 1173 DIR. You can also set the `AC_MACRODIR' environment variable to a 1174 directory; this option overrides the environment variable. 1175 1176`--version' 1177 Print the version number of Autoconf and exit. 1178 1179 1180File: autoconf.info, Node: Subdirectories, Next: Default Prefix, Prev: Configuration Headers, Up: Setup 1181 1182Configuring Other Packages in Subdirectories 1183============================================ 1184 1185 In most situations, calling `AC_OUTPUT' is sufficient to produce 1186`Makefile's in subdirectories. However, `configure' scripts that 1187control more than one independent package can use `AC_CONFIG_SUBDIRS' 1188to run `configure' scripts for other packages in subdirectories. 1189 1190 - Macro: AC_CONFIG_SUBDIRS (DIR ...) 1191 Make `AC_OUTPUT' run `configure' in each subdirectory DIR in the 1192 given whitespace-separated list. If a given DIR is not found, no 1193 error is reported, so a `configure' script can configure whichever 1194 parts of a large source tree are present. If a given DIR contains 1195 `configure.in' but no `configure', the Cygnus `configure' script 1196 found by `AC_CONFIG_AUXDIR' is used. 1197 1198 The subdirectory `configure' scripts are given the same command 1199 line options that were given to this `configure' script, with 1200 minor changes if needed (e.g., to adjust a relative path for the 1201 cache file or source directory). This macro also sets the output 1202 variable `subdirs' to the list of directories `DIR ...'. 1203 `Makefile' rules can use this variable to determine which 1204 subdirectories to recurse into. This macro may be called multiple 1205 times. 1206 1207 1208File: autoconf.info, Node: Default Prefix, Next: Versions, Prev: Subdirectories, Up: Setup 1209 1210Default Prefix 1211============== 1212 1213 By default, `configure' sets the prefix for files it installs to 1214`/usr/local'. The user of `configure' can select a different prefix 1215using the `--prefix' and `--exec-prefix' options. There are two ways 1216to change the default: when creating `configure', and when running it. 1217 1218 Some software packages might want to install in a directory besides 1219`/usr/local' by default. To accomplish that, use the 1220`AC_PREFIX_DEFAULT' macro. 1221 1222 - Macro: AC_PREFIX_DEFAULT (PREFIX) 1223 Set the default installation prefix to PREFIX instead of 1224 `/usr/local'. 1225 1226 It may be convenient for users to have `configure' guess the 1227installation prefix from the location of a related program that they 1228have already installed. If you wish to do that, you can call 1229`AC_PREFIX_PROGRAM'. 1230 1231 - Macro: AC_PREFIX_PROGRAM (PROGRAM) 1232 If the user did not specify an installation prefix (using the 1233 `--prefix' option), guess a value for it by looking for PROGRAM in 1234 `PATH', the way the shell does. If PROGRAM is found, set the 1235 prefix to the parent of the directory containing PROGRAM; 1236 otherwise leave the prefix specified in `Makefile.in' unchanged. 1237 For example, if PROGRAM is `gcc' and the `PATH' contains 1238 `/usr/local/gnu/bin/gcc', set the prefix to `/usr/local/gnu'. 1239 1240 1241File: autoconf.info, Node: Versions, Prev: Default Prefix, Up: Setup 1242 1243Version Numbers in `configure' 1244============================== 1245 1246 The following macros manage version numbers for `configure' scripts. 1247Using them is optional. 1248 1249 - Macro: AC_PREREQ (VERSION) 1250 Ensure that a recent enough version of Autoconf is being used. If 1251 the version of Autoconf being used to create `configure' is earlier 1252 than VERSION, print an error message on the standard error output 1253 and do not create `configure'. For example: 1254 1255 AC_PREREQ(1.8) 1256 1257 This macro is useful if your `configure.in' relies on non-obvious 1258 behavior that changed between Autoconf releases. If it merely 1259 needs recently added macros, then `AC_PREREQ' is less useful, 1260 because the `autoconf' program already tells the user which macros 1261 are not found. The same thing happens if `configure.in' is 1262 processed by a version of Autoconf older than when `AC_PREREQ' was 1263 added. 1264 1265 - Macro: AC_REVISION (REVISION-INFO) 1266 Copy revision stamp REVISION-INFO into the `configure' script, 1267 with any dollar signs or double-quotes removed. This macro lets 1268 you put a revision stamp from `configure.in' into `configure' 1269 without RCS or CVS changing it when you check in `configure'. That 1270 way, you can determine easily which revision of `configure.in' a 1271 particular `configure' corresponds to. 1272 1273 It is a good idea to call this macro before `AC_INIT' so that the 1274 revision number is near the top of both `configure.in' and 1275 `configure'. To support doing that, the `AC_REVISION' output 1276 begins with `#! /bin/sh', like the normal start of a `configure' 1277 script does. 1278 1279 For example, this line in `configure.in': 1280 1281 AC_REVISION($Revision: 1.30 $)dnl 1282 1283 produces this in `configure': 1284 1285 #! /bin/sh 1286 # From configure.in Revision: 1.30 1287 1288 1289File: autoconf.info, Node: Existing Tests, Next: Writing Tests, Prev: Setup, Up: Top 1290 1291Existing Tests 1292************** 1293 1294 These macros test for particular system features that packages might 1295need or want to use. If you need to test for a kind of feature that 1296none of these macros check for, you can probably do it by calling 1297primitive test macros with appropriate arguments (*note Writing 1298Tests::.). 1299 1300 These tests print messages telling the user which feature they're 1301checking for, and what they find. They cache their results for future 1302`configure' runs (*note Caching Results::.). 1303 1304 Some of these macros set output variables. *Note Makefile 1305Substitutions::, for how to get their values. The phrase "define NAME" 1306is used below as a shorthand to mean "define C preprocessor symbol NAME 1307to the value 1". *Note Defining Symbols::, for how to get those symbol 1308definitions into your program. 1309 1310* Menu: 1311 1312* Alternative Programs:: Selecting between alternative programs. 1313* Libraries:: Library archives that might be missing. 1314* Library Functions:: C library functions that might be missing. 1315* Header Files:: Header files that might be missing. 1316* Structures:: Structures or members that might be missing. 1317* Typedefs:: `typedef's that might be missing. 1318* C Compiler Characteristics:: 1319* Fortran 77 Compiler Characteristics:: 1320* System Services:: Operating system services. 1321* UNIX Variants:: Special kludges for specific UNIX variants. 1322 1323 1324File: autoconf.info, Node: Alternative Programs, Next: Libraries, Prev: Existing Tests, Up: Existing Tests 1325 1326Alternative Programs 1327==================== 1328 1329 These macros check for the presence or behavior of particular 1330programs. They are used to choose between several alternative programs 1331and to decide what to do once one has been chosen. If there is no 1332macro specifically defined to check for a program you need, and you 1333don't need to check for any special properties of it, then you can use 1334one of the general program check macros. 1335 1336* Menu: 1337 1338* Particular Programs:: Special handling to find certain programs. 1339* Generic Programs:: How to find other programs. 1340 1341 1342File: autoconf.info, Node: Particular Programs, Next: Generic Programs, Prev: Alternative Programs, Up: Alternative Programs 1343 1344Particular Program Checks 1345------------------------- 1346 1347 These macros check for particular programs--whether they exist, and 1348in some cases whether they support certain features. 1349 1350 - Macro: AC_DECL_YYTEXT 1351 Define `YYTEXT_POINTER' if `yytext' is a `char *' instead of a 1352 `char []'. Also set output variable `LEX_OUTPUT_ROOT' to the base 1353 of the file name that the lexer generates; usually `lex.yy', but 1354 sometimes something else. These results vary according to whether 1355 `lex' or `flex' is being used. 1356 1357 - Macro: AC_PROG_AWK 1358 Check for `mawk', `gawk', `nawk', and `awk', in that order, and 1359 set output variable `AWK' to the first one that it finds. It 1360 tries `mawk' first because that is reported to be the fastest 1361 implementation. 1362 1363 - Macro: AC_PROG_CC 1364 Determine a C compiler to use. If `CC' is not already set in the 1365 environment, check for `gcc', and use `cc' if that's not found. 1366 Set output variable `CC' to the name of the compiler found. 1367 1368 If using the GNU C compiler, set shell variable `GCC' to `yes', 1369 empty otherwise. If output variable `CFLAGS' was not already set, 1370 set it to `-g -O2' for the GNU C compiler (`-O2' on systems where 1371 GCC does not accept `-g'), or `-g' for other compilers. 1372 1373 If the C compiler being used does not produce executables that can 1374 run on the system where `configure' is being run, set the shell 1375 variable `cross_compiling' to `yes', otherwise `no'. In other 1376 words, this tests whether the build system type is different from 1377 the host system type (the target system type is irrelevant to this 1378 test). *Note Manual Configuration::, for more on support for 1379 cross compiling. 1380 1381 - Macro: AC_PROG_CC_C_O 1382 If the C compiler does not accept the `-c' and `-o' options 1383 simultaneously, define `NO_MINUS_C_MINUS_O'. 1384 1385 - Macro: AC_PROG_CPP 1386 Set output variable `CPP' to a command that runs the C 1387 preprocessor. If `$CC -E' doesn't work, it uses `/lib/cpp'. It 1388 is only portable to run `CPP' on files with a `.c' extension. 1389 1390 If the current language is C (*note Language Choice::.), many of 1391 the specific test macros use the value of `CPP' indirectly by 1392 calling `AC_TRY_CPP', `AC_CHECK_HEADER', `AC_EGREP_HEADER', or 1393 `AC_EGREP_CPP'. 1394 1395 - Macro: AC_PROG_CXX 1396 Determine a C++ compiler to use. Check if the environment variable 1397 `CXX' or `CCC' (in that order) is set; if so, set output variable 1398 `CXX' to its value. Otherwise search for a C++ compiler under 1399 likely names (`c++', `g++', `gcc', `CC', `cxx', and `cc++'). If 1400 none of those checks succeed, as a last resort set `CXX' to `gcc'. 1401 1402 If using the GNU C++ compiler, set shell variable `GXX' to `yes', 1403 empty otherwise. If output variable `CXXFLAGS' was not already 1404 set, set it to `-g -O2' for the GNU C++ compiler (`-O2' on systems 1405 where G++ does not accept `-g'), or `-g' for other compilers. 1406 1407 If the C++ compiler being used does not produce executables that 1408 can run on the system where `configure' is being run, set the shell 1409 variable `cross_compiling' to `yes', otherwise `no'. In other 1410 words, this tests whether the build system type is different from 1411 the host system type (the target system type is irrelevant to this 1412 test). *Note Manual Configuration::, for more on support for 1413 cross compiling. 1414 1415 - Macro: AC_PROG_CXXCPP 1416 Set output variable `CXXCPP' to a command that runs the C++ 1417 preprocessor. If `$CXX -E' doesn't work, it uses `/lib/cpp'. It 1418 is only portable to run `CXXCPP' on files with a `.c', `.C', or 1419 `.cc' extension. 1420 1421 If the current language is C++ (*note Language Choice::.), many of 1422 the specific test macros use the value of `CXXCPP' indirectly by 1423 calling `AC_TRY_CPP', `AC_CHECK_HEADER', `AC_EGREP_HEADER', or 1424 `AC_EGREP_CPP'. 1425 1426 - Macro: AC_PROG_F77 1427 Determine a Fortran 77 compiler to use. If `F77' is not already 1428 set in the environment, check for `g77', `f77' and `f2c', in that 1429 order. Set the output variable `F77' to the name of the compiler 1430 found. 1431 1432 If using `g77' (the GNU Fortran 77 compiler), then `AC_PROG_F77' 1433 will set the shell variable `G77' to `yes', and empty otherwise. 1434 If the output variable `FFLAGS' was not already set in the 1435 environment, then set it to `-g -02' for `g77' (or `-O2' where 1436 `g77' does not accept `-g'). Otherwise, set `FFLAGS' to `-g' for 1437 all other Fortran 77 compilers. 1438 1439 - Macro: AC_PROG_F77_C_O 1440 Test if the Fortran 77 compiler accepts the options `-c' and `-o' 1441 simultaneously, and define `F77_NO_MINUS_C_MINUS_O' if it does not. 1442 1443 - Macro: AC_PROG_GCC_TRADITIONAL 1444 Add `-traditional' to output variable `CC' if using the GNU C 1445 compiler and `ioctl' does not work properly without 1446 `-traditional'. That usually happens when the fixed header files 1447 have not been installed on an old system. Since recent versions 1448 of the GNU C compiler fix the header files automatically when 1449 installed, this is becoming a less prevalent problem. 1450 1451 - Macro: AC_PROG_INSTALL 1452 Set output variable `INSTALL' to the path of a BSD compatible 1453 `install' program, if one is found in the current `PATH'. 1454 Otherwise, set `INSTALL' to `DIR/install-sh -c', checking the 1455 directories specified to `AC_CONFIG_AUX_DIR' (or its default 1456 directories) to determine DIR (*note Output::.). Also set the 1457 variables `INSTALL_PROGRAM' and `INSTALL_SCRIPT' to `${INSTALL}' 1458 and `INSTALL_DATA' to `${INSTALL} -m 644'. 1459 1460 This macro screens out various instances of `install' known to not 1461 work. It prefers to find a C program rather than a shell script, 1462 for speed. Instead of `install-sh', it can also use `install.sh', 1463 but that name is obsolete because some `make' programs have a rule 1464 that creates `install' from it if there is no `Makefile'. 1465 1466 A copy of `install-sh' which you may use comes with Autoconf. If 1467 you use `AC_PROG_INSTALL', you must include either `install-sh' or 1468 `install.sh' in your distribution, or `configure' will produce an 1469 error message saying it can't find them--even if the system you're 1470 on has a good `install' program. This check is a safety measure 1471 to prevent you from accidentally leaving that file out, which 1472 would prevent your package from installing on systems that don't 1473 have a BSD-compatible `install' program. 1474 1475 If you need to use your own installation program because it has 1476 features not found in standard `install' programs, there is no 1477 reason to use `AC_PROG_INSTALL'; just put the pathname of your 1478 program into your `Makefile.in' files. 1479 1480 - Macro: AC_PROG_LEX 1481 If `flex' is found, set output variable `LEX' to `flex' and 1482 `LEXLIB' to `-lfl', if that library is in a standard place. 1483 Otherwise set `LEX' to `lex' and `LEXLIB' to `-ll'. 1484 1485 - Macro: AC_PROG_LN_S 1486 If `ln -s' works on the current filesystem (the operating system 1487 and filesystem support symbolic links), set output variable `LN_S' 1488 to `ln -s', otherwise set it to `ln'. 1489 1490 If the link is put in a directory other than the current 1491 directory, its meaning depends on whether `ln' or `ln -s' is used. 1492 To safely create links using `$(LN_S)', either find out which 1493 form is used and adjust the arguments, or always invoke `ln' in 1494 the directory where the link is to be created. 1495 1496 In other words, it does not work to do 1497 $(LN_S) foo /x/bar 1498 1499 Instead, do 1500 1501 (cd /x && $(LN_S) foo bar) 1502 1503 - Macro: AC_PROG_RANLIB 1504 Set output variable `RANLIB' to `ranlib' if `ranlib' is found, 1505 otherwise to `:' (do nothing). 1506 1507 - Macro: AC_PROG_YACC 1508 If `bison' is found, set output variable `YACC' to `bison -y'. 1509 Otherwise, if `byacc' is found, set `YACC' to `byacc'. Otherwise 1510 set `YACC' to `yacc'. 1511 1512 1513File: autoconf.info, Node: Generic Programs, Prev: Particular Programs, Up: Alternative Programs 1514 1515Generic Program and File Checks 1516------------------------------- 1517 1518 These macros are used to find programs not covered by the particular 1519test macros. If you need to check the behavior of a program as well as 1520find out whether it is present, you have to write your own test for it 1521(*note Writing Tests::.). By default, these macros use the environment 1522variable `PATH'. If you need to check for a program that might not be 1523in the user's `PATH', you can pass a modified path to use instead, like 1524this: 1525 1526 AC_PATH_PROG(INETD, inetd, /usr/libexec/inetd, 1527 $PATH:/usr/libexec:/usr/sbin:/usr/etc:etc) 1528 1529 - Macro: AC_CHECK_FILE (FILE [, ACTION-IF-FOUND [, 1530 ACTION-IF-NOT-FOUND]]) 1531 Check whether file FILE exists on the native system. If it is 1532 found, execute ACTION-IF-FOUND, otherwise do ACTION-IF-NOT-FOUND, 1533 if given. 1534 1535 - Macro: AC_CHECK_FILES (FILES[, ACTION-IF-FOUND [, 1536 ACTION-IF-NOT-FOUND]]) 1537 Executes `AC_CHECK_FILE' once for each file listed in FILES. 1538 Additionally, defines `HAVEFILE' for each file found, set to 1. 1539 1540 - Macro: AC_CHECK_PROG (VARIABLE, PROG-TO-CHECK-FOR, VALUE-IF-FOUND [, 1541 VALUE-IF-NOT-FOUND [, PATH, [ REJECT ]]]) 1542 Check whether program PROG-TO-CHECK-FOR exists in `PATH'. If it 1543 is found, set VARIABLE to VALUE-IF-FOUND, otherwise to 1544 VALUE-IF-NOT-FOUND, if given. Always pass over REJECT (an 1545 absolute file name) even if it is the first found in the search 1546 path; in that case, set VARIABLE using the absolute file name of 1547 the PROG-TO-CHECK-FOR found that is not REJECT. If VARIABLE was 1548 already set, do nothing. Calls `AC_SUBST' for VARIABLE. 1549 1550 - Macro: AC_CHECK_PROGS (VARIABLE, PROGS-TO-CHECK-FOR [, 1551 VALUE-IF-NOT-FOUND [, PATH]]) 1552 Check for each program in the whitespace-separated list 1553 PROGS-TO-CHECK-FOR exists in `PATH'. If it is found, set VARIABLE 1554 to the name of that program. Otherwise, continue checking the 1555 next program in the list. If none of the programs in the list are 1556 found, set VARIABLE to VALUE-IF-NOT-FOUND; if VALUE-IF-NOT-FOUND 1557 is not specified, the value of VARIABLE is not changed. Calls 1558 `AC_SUBST' for VARIABLE. 1559 1560 - Macro: AC_CHECK_TOOL (VARIABLE, PROG-TO-CHECK-FOR [, 1561 VALUE-IF-NOT-FOUND [, PATH]]) 1562 Like `AC_CHECK_PROG', but first looks for PROG-TO-CHECK-FOR with a 1563 prefix of the host type as determined by `AC_CANONICAL_HOST', 1564 followed by a dash (*note Canonicalizing::.). For example, if the 1565 user runs `configure --host=i386-gnu', then this call: 1566 AC_CHECK_TOOL(RANLIB, ranlib, :) 1567 1568 sets `RANLIB' to `i386-gnu-ranlib' if that program exists in 1569 `PATH', or to `ranlib' if that program exists in `PATH', or to `:' 1570 if neither program exists. 1571 1572 - Macro: AC_PATH_PROG (VARIABLE, PROG-TO-CHECK-FOR [, 1573 VALUE-IF-NOT-FOUND [, PATH]]) 1574 Like `AC_CHECK_PROG', but set VARIABLE to the entire path of 1575 PROG-TO-CHECK-FOR if found. 1576 1577 - Macro: AC_PATH_PROGS (VARIABLE, PROGS-TO-CHECK-FOR [, 1578 VALUE-IF-NOT-FOUND [, PATH]]) 1579 Like `AC_CHECK_PROGS', but if any of PROGS-TO-CHECK-FOR are found, 1580 set VARIABLE to the entire path of the program found. 1581 1582 1583File: autoconf.info, Node: Libraries, Next: Library Functions, Prev: Alternative Programs, Up: Existing Tests 1584 1585Library Files 1586============= 1587 1588 The following macros check for the presence of certain C, C++ or 1589Fortran 77 library archive files. 1590 1591 - Macro: AC_CHECK_LIB (LIBRARY, FUNCTION [, ACTION-IF-FOUND [, 1592 ACTION-IF-NOT-FOUND [, OTHER-LIBRARIES]]]) 1593 Depending on the current language(*note Language Choice::.), try to 1594 ensure that the C, C++ or Fortran 77 function FUNCTION is 1595 available by checking whether a test program can be linked with the 1596 library LIBRARY to get the function. LIBRARY is the base name of 1597 the library; e.g., to check for `-lmp', use `mp' as the LIBRARY 1598 argument. 1599 1600 ACTION-IF-FOUND is a list of shell commands to run if the link 1601 with the library succeeds; ACTION-IF-NOT-FOUND is a list of shell 1602 commands to run if the link fails. If ACTION-IF-FOUND is not 1603 specified, the default action will add `-lLIBRARY' to `LIBS' and 1604 define `HAVE_LIBLIBRARY' (in all capitals). 1605 1606 If linking with LIBRARY results in unresolved symbols, which would 1607 be resolved by linking with additional libraries, give those 1608 libraries as the OTHER-LIBRARIES argument, separated by spaces: 1609 `-lXt -lX11'. Otherwise this macro will fail to detect that 1610 LIBRARY is present, because linking the test program will always 1611 fail with unresolved symbols. 1612 1613 - Macro: AC_HAVE_LIBRARY (LIBRARY, [, ACTION-IF-FOUND [, 1614 ACTION-IF-NOT-FOUND [, OTHER-LIBRARIES]]]) 1615 This macro is equivalent to calling `AC_CHECK_LIB' with a FUNCTION 1616 argument of `main'. In addition, LIBRARY can be written as any of 1617 `foo', `-lfoo', or `libfoo.a'. In all of those cases, the 1618 compiler is passed `-lfoo'. However, LIBRARY can not be a shell 1619 variable; it must be a literal name. This macro is considered 1620 obsolete. 1621 1622 - Macro: AC_SEARCH_LIBS (FUNCTION, SEARCH-LIBS [, ACTION-IF-FOUND [, 1623 ACTION-IF-NOT-FOUND [, OTHER-LIBRARIES]]]) 1624 Search for a library defining FUNCTION, if it's not already 1625 available. This equates to calling `AC_TRY_LINK_FUNC' first with 1626 no libraries, then for each library listed in SEARCH-LIBS. 1627 1628 If the function is found, run ACTION-IF-FOUND, otherwise run 1629 ACTION-IF-NOT-FOUND. 1630 1631 If linking with LIBRARY results in unresolved symbols, which would 1632 be resolved by linking with additional libraries, give those 1633 libraries as the OTHER-LIBRARIES argument, separated by spaces: 1634 `-lXt -lX11'. Otherwise this macro will fail to detect that 1635 FUNCTION is present, because linking the test program will always 1636 fail with unresolved symbols. 1637 1638 - Macro: AC_SEARCH_LIBS (FUNCTION, SEARCH-LIBS[, ACTION-IF-FOUND [, 1639 ACTION-IF-NOT-FOUND]]) 1640 This macro is equivalent to calling `AC_TRY_LINK_FUNC' once for 1641 each library listed in SEARCH-LIBS. Add `-lLIBRARY' to `LIBS' for 1642 the first library found to contain FUNCTION, and execute 1643 ACTION-IF-FOUND. Otherwise execute ACTION-IF-NOT-FOUND. 1644 1645 1646File: autoconf.info, Node: Library Functions, Next: Header Files, Prev: Libraries, Up: Existing Tests 1647 1648Library Functions 1649================= 1650 1651 The following macros check for particular C library functions. If 1652there is no macro specifically defined to check for a function you need, 1653and you don't need to check for any special properties of it, then you 1654can use one of the general function check macros. 1655 1656* Menu: 1657 1658* Particular Functions:: Special handling to find certain functions. 1659* Generic Functions:: How to find other functions. 1660 1661 1662File: autoconf.info, Node: Particular Functions, Next: Generic Functions, Prev: Library Functions, Up: Library Functions 1663 1664Particular Function Checks 1665-------------------------- 1666 1667 These macros check for particular C functions--whether they exist, 1668and in some cases how they respond when given certain arguments. 1669 1670 - Macro: AC_FUNC_ALLOCA 1671 Check how to get `alloca'. Tries to get a builtin version by 1672 checking for `alloca.h' or the predefined C preprocessor macros 1673 `__GNUC__' and `_AIX'. If this macro finds `alloca.h', it defines 1674 `HAVE_ALLOCA_H'. 1675 1676 If those attempts fail, it looks for the function in the standard C 1677 library. If any of those methods succeed, it defines 1678 `HAVE_ALLOCA'. Otherwise, it sets the output variable `ALLOCA' to 1679 `alloca.o' and defines `C_ALLOCA' (so programs can periodically 1680 call `alloca(0)' to garbage collect). This variable is separate 1681 from `LIBOBJS' so multiple programs can share the value of 1682 `ALLOCA' without needing to create an actual library, in case only 1683 some of them use the code in `LIBOBJS'. 1684 1685 This macro does not try to get `alloca' from the System V R3 1686 `libPW' or the System V R4 `libucb' because those libraries 1687 contain some incompatible functions that cause trouble. Some 1688 versions do not even contain `alloca' or contain a buggy version. 1689 If you still want to use their `alloca', use `ar' to extract 1690 `alloca.o' from them instead of compiling `alloca.c'. 1691 1692 Source files that use `alloca' should start with a piece of code 1693 like the following, to declare it properly. In some versions of 1694 AIX, the declaration of `alloca' must precede everything else 1695 except for comments and preprocessor directives. The `#pragma' 1696 directive is indented so that pre-ANSI C compilers will ignore it, 1697 rather than choke on it. 1698 1699 /* AIX requires this to be the first thing in the file. */ 1700 #ifndef __GNUC__ 1701 # if HAVE_ALLOCA_H 1702 # include <alloca.h> 1703 # else 1704 # ifdef _AIX 1705 #pragma alloca 1706 # else 1707 # ifndef alloca /* predefined by HP cc +Olibcalls */ 1708 char *alloca (); 1709 # endif 1710 # endif 1711 # endif 1712 #endif 1713 1714 - Macro: AC_FUNC_CLOSEDIR_VOID 1715 If the `closedir' function does not return a meaningful value, 1716 define `CLOSEDIR_VOID'. Otherwise, callers ought to check its 1717 return value for an error indicator. 1718 1719 - Macro: AC_FUNC_FNMATCH 1720 If the `fnmatch' function is available and works (unlike the one on 1721 SunOS 5.4), define `HAVE_FNMATCH'. 1722 1723 - Macro: AC_FUNC_GETLOADAVG 1724 Check how to get the system load averages. If the system has the 1725 `getloadavg' function, this macro defines `HAVE_GETLOADAVG', and 1726 adds to `LIBS' any libraries needed to get that function. 1727 1728 Otherwise, it adds `getloadavg.o' to the output variable 1729 `LIBOBJS', and possibly defines several other C preprocessor 1730 macros and output variables: 1731 1732 1. It defines `SVR4', `DGUX', `UMAX', or `UMAX4_3' if on those 1733 systems. 1734 1735 2. If it finds `nlist.h', it defines `NLIST_STRUCT'. 1736 1737 3. If `struct nlist' has an `n_un' member, it defines 1738 `NLIST_NAME_UNION'. 1739 1740 4. If compiling `getloadavg.c' defines `LDAV_PRIVILEGED', 1741 programs need to be installed specially on this system for 1742 `getloadavg' to work, and this macro defines 1743 `GETLOADAVG_PRIVILEGED'. 1744 1745 5. This macro sets the output variable `NEED_SETGID'. The value 1746 is `true' if special installation is required, `false' if not. 1747 If `NEED_SETGID' is `true', this macro sets `KMEM_GROUP' to 1748 the name of the group that should own the installed program. 1749 1750 - Macro: AC_FUNC_GETMNTENT 1751 Check for `getmntent' in the `sun', `seq', and `gen' libraries, 1752 for Irix 4, PTX, and Unixware, respectively. Then, if `getmntent' 1753 is available, define `HAVE_GETMNTENT'. 1754 1755 - Macro: AC_FUNC_GETPGRP 1756 If `getpgrp' takes no argument (the POSIX.1 version), define 1757 `GETPGRP_VOID'. Otherwise, it is the BSD version, which takes a 1758 process ID as an argument. This macro does not check whether 1759 `getpgrp' exists at all; if you need to work in that situation, 1760 first call `AC_CHECK_FUNC' for `getpgrp'. 1761 1762 - Macro: AC_FUNC_MEMCMP 1763 If the `memcmp' function is not available, or does not work on 1764 8-bit data (like the one on SunOS 4.1.3), add `memcmp.o' to output 1765 variable `LIBOBJS'. 1766 1767 - Macro: AC_FUNC_MMAP 1768 If the `mmap' function exists and works correctly, define 1769 `HAVE_MMAP'. Only checks private fixed mapping of already-mapped 1770 memory. 1771 1772 - Macro: AC_FUNC_SELECT_ARGTYPES 1773 Determines the correct type to be passed to each of the `select' 1774 function's arguments, and defines those types in 1775 `SELECT_TYPE_ARG1', `SELECT_TYPE_ARG234', and `SELECT_TYPE_ARG5' 1776 respectively. `SELECT_TYPE_ARG1' defaults to `int', 1777 `SELECT_TYPE_ARG234' defaults to `int *', and `SELECT_TYPE_ARG5' 1778 defaults to `struct timeval *'. 1779 1780 - Macro: AC_FUNC_SETPGRP 1781 If `setpgrp' takes no argument (the POSIX.1 version), define 1782 `SETPGRP_VOID'. Otherwise, it is the BSD version, which takes two 1783 process ID as arguments. This macro does not check whether 1784 `setpgrp' exists at all; if you need to work in that situation, 1785 first call `AC_CHECK_FUNC' for `setpgrp'. 1786 1787 - Macro: AC_FUNC_SETVBUF_REVERSED 1788 If `setvbuf' takes the buffering type as its second argument and 1789 the buffer pointer as the third, instead of the other way around, 1790 define `SETVBUF_REVERSED'. This is the case on System V before 1791 release 3. 1792 1793 - Macro: AC_FUNC_STRCOLL 1794 If the `strcoll' function exists and works correctly, define 1795 `HAVE_STRCOLL'. This does a bit more than 1796 `AC_CHECK_FUNCS(strcoll)', because some systems have incorrect 1797 definitions of `strcoll', which should not be used. 1798 1799 - Macro: AC_FUNC_STRFTIME 1800 Check for `strftime' in the `intl' library, for SCO UNIX. Then, 1801 if `strftime' is available, define `HAVE_STRFTIME'. 1802 1803 - Macro: AC_FUNC_UTIME_NULL 1804 If `utime(FILE, NULL)' sets FILE's timestamp to the present, 1805 define `HAVE_UTIME_NULL'. 1806 1807 - Macro: AC_FUNC_VFORK 1808 If `vfork.h' is found, define `HAVE_VFORK_H'. If a working 1809 `vfork' is not found, define `vfork' to be `fork'. This macro 1810 checks for several known errors in implementations of `vfork' and 1811 considers the system to not have a working `vfork' if it detects 1812 any of them. It is not considered to be an implementation error 1813 if a child's invocation of `signal' modifies the parent's signal 1814 handler, since child processes rarely change their signal handlers. 1815 1816 - Macro: AC_FUNC_VPRINTF 1817 If `vprintf' is found, define `HAVE_VPRINTF'. Otherwise, if 1818 `_doprnt' is found, define `HAVE_DOPRNT'. (If `vprintf' is 1819 available, you may assume that `vfprintf' and `vsprintf' are also 1820 available.) 1821 1822 - Macro: AC_FUNC_WAIT3 1823 If `wait3' is found and fills in the contents of its third argument 1824 (a `struct rusage *'), which HP-UX does not do, define 1825 `HAVE_WAIT3'. 1826 1827 1828File: autoconf.info, Node: Generic Functions, Prev: Particular Functions, Up: Library Functions 1829 1830Generic Function Checks 1831----------------------- 1832 1833 These macros are used to find functions not covered by the particular 1834test macros. If the functions might be in libraries other than the 1835default C library, first call `AC_CHECK_LIB' for those libraries. If 1836you need to check the behavior of a function as well as find out 1837whether it is present, you have to write your own test for it (*note 1838Writing Tests::.). 1839 1840 - Macro: AC_CHECK_FUNC (FUNCTION, [ACTION-IF-FOUND [, 1841 ACTION-IF-NOT-FOUND]]) 1842 If C function FUNCTION is available, run shell commands 1843 ACTION-IF-FOUND, otherwise ACTION-IF-NOT-FOUND. If you just want 1844 to define a symbol if the function is available, consider using 1845 `AC_CHECK_FUNCS' instead. This macro checks for functions with C 1846 linkage even when `AC_LANG_CPLUSPLUS' has been called, since C++ is 1847 more standardized than C is. (*note Language Choice::., for more 1848 information about selecting the language for checks.) 1849 1850 - Macro: AC_CHECK_FUNCS (FUNCTION... [, ACTION-IF-FOUND [, 1851 ACTION-IF-NOT-FOUND]]) 1852 For each given FUNCTION in the whitespace-separated argument list 1853 that is available, define `HAVE_FUNCTION' (in all capitals). If 1854 ACTION-IF-FOUND is given, it is additional shell code to execute 1855 when one of the functions is found. You can give it a value of 1856 `break' to break out of the loop on the first match. If 1857 ACTION-IF-NOT-FOUND is given, it is executed when one of the 1858 functions is not found. 1859 1860 - Macro: AC_REPLACE_FUNCS (FUNCTION...) 1861 Like calling `AC_CHECK_FUNCS' using an ACTION-IF-NOT-FOUND that 1862 adds `FUNCTION.o' to the value of the output variable `LIBOBJS'. 1863 You can declare a function for which your replacement version is 1864 used by enclosing the prototype in `#ifndef HAVE_FUNCTION'. If 1865 the system has the function, it probably declares it in a header 1866 file you should be including, so you shouldn't redeclare it, lest 1867 your declaration conflict. 1868 1869 1870File: autoconf.info, Node: Header Files, Next: Structures, Prev: Library Functions, Up: Existing Tests 1871 1872Header Files 1873============ 1874 1875 The following macros check for the presence of certain C header 1876files. If there is no macro specifically defined to check for a header 1877file you need, and you don't need to check for any special properties of 1878it, then you can use one of the general header file check macros. 1879 1880* Menu: 1881 1882* Particular Headers:: Special handling to find certain headers. 1883* Generic Headers:: How to find other headers. 1884 1885 1886File: autoconf.info, Node: Particular Headers, Next: Generic Headers, Prev: Header Files, Up: Header Files 1887 1888Particular Header Checks 1889------------------------ 1890 1891 These macros check for particular system header files--whether they 1892exist, and in some cases whether they declare certain symbols. 1893 1894 - Macro: AC_DECL_SYS_SIGLIST 1895 Define `SYS_SIGLIST_DECLARED' if the variable `sys_siglist' is 1896 declared in a system header file, either `signal.h' or `unistd.h'. 1897 1898 - Macro: AC_DIR_HEADER 1899 Like calling `AC_HEADER_DIRENT' and `AC_FUNC_CLOSEDIR_VOID', but 1900 defines a different set of C preprocessor macros to indicate which 1901 header file is found. This macro and the names it defines are 1902 considered obsolete. The names it defines are: 1903 1904 `dirent.h' 1905 `DIRENT' 1906 1907 `sys/ndir.h' 1908 `SYSNDIR' 1909 1910 `sys/dir.h' 1911 `SYSDIR' 1912 1913 `ndir.h' 1914 `NDIR' 1915 1916 In addition, if the `closedir' function does not return a 1917 meaningful value, define `VOID_CLOSEDIR'. 1918 1919 - Macro: AC_HEADER_DIRENT 1920 Check for the following header files, and for the first one that is 1921 found and defines `DIR', define the listed C preprocessor macro: 1922 1923 `dirent.h' 1924 `HAVE_DIRENT_H' 1925 1926 `sys/ndir.h' 1927 `HAVE_SYS_NDIR_H' 1928 1929 `sys/dir.h' 1930 `HAVE_SYS_DIR_H' 1931 1932 `ndir.h' 1933 `HAVE_NDIR_H' 1934 1935 The directory library declarations in the source code should look 1936 something like the following: 1937 1938 #if HAVE_DIRENT_H 1939 # include <dirent.h> 1940 # define NAMLEN(dirent) strlen((dirent)->d_name) 1941 #else 1942 # define dirent direct 1943 # define NAMLEN(dirent) (dirent)->d_namlen 1944 # if HAVE_SYS_NDIR_H 1945 # include <sys/ndir.h> 1946 # endif 1947 # if HAVE_SYS_DIR_H 1948 # include <sys/dir.h> 1949 # endif 1950 # if HAVE_NDIR_H 1951 # include <ndir.h> 1952 # endif 1953 #endif 1954 1955 Using the above declarations, the program would declare variables 1956 to be type `struct dirent', not `struct direct', and would access 1957 the length of a directory entry name by passing a pointer to a 1958 `struct dirent' to the `NAMLEN' macro. 1959 1960 This macro also checks for the SCO Xenix `dir' and `x' libraries. 1961 1962 - Macro: AC_HEADER_MAJOR 1963 If `sys/types.h' does not define `major', `minor', and `makedev', 1964 but `sys/mkdev.h' does, define `MAJOR_IN_MKDEV'; otherwise, if 1965 `sys/sysmacros.h' does, define `MAJOR_IN_SYSMACROS'. 1966 1967 - Macro: AC_HEADER_STDC 1968 Define `STDC_HEADERS' if the system has ANSI C header files. 1969 Specifically, this macro checks for `stdlib.h', `stdarg.h', 1970 `string.h', and `float.h'; if the system has those, it probably 1971 has the rest of the ANSI C header files. This macro also checks 1972 whether `string.h' declares `memchr' (and thus presumably the 1973 other `mem' functions), whether `stdlib.h' declare `free' (and 1974 thus presumably `malloc' and other related functions), and whether 1975 the `ctype.h' macros work on characters with the high bit set, as 1976 ANSI C requires. 1977 1978 Use `STDC_HEADERS' instead of `__STDC__' to determine whether the 1979 system has ANSI-compliant header files (and probably C library 1980 functions) because many systems that have GCC do not have ANSI C 1981 header files. 1982 1983 On systems without ANSI C headers, there is so much variation that 1984 it is probably easier to declare the functions you use than to 1985 figure out exactly what the system header files declare. Some 1986 systems contain a mix of functions ANSI and BSD; some are mostly 1987 ANSI but lack `memmove'; some define the BSD functions as macros in 1988 `string.h' or `strings.h'; some have only the BSD functions but 1989 `string.h'; some declare the memory functions in `memory.h', some 1990 in `string.h'; etc. It is probably sufficient to check for one 1991 string function and one memory function; if the library has the 1992 ANSI versions of those then it probably has most of the others. 1993 If you put the following in `configure.in': 1994 1995 AC_HEADER_STDC 1996 AC_CHECK_FUNCS(strchr memcpy) 1997 1998 then, in your code, you can put declarations like this: 1999 2000 #if STDC_HEADERS 2001 # include <string.h> 2002 #else 2003 # ifndef HAVE_STRCHR 2004 # define strchr index 2005 # define strrchr rindex 2006 # endif 2007 char *strchr (), *strrchr (); 2008 # ifndef HAVE_MEMCPY 2009 # define memcpy(d, s, n) bcopy ((s), (d), (n)) 2010 # define memmove(d, s, n) bcopy ((s), (d), (n)) 2011 # endif 2012 #endif 2013 2014 If you use a function like `memchr', `memset', `strtok', or 2015 `strspn', which have no BSD equivalent, then macros won't suffice; 2016 you must provide an implementation of each function. An easy way 2017 to incorporate your implementations only when needed (since the 2018 ones in system C libraries may be hand optimized) is to, taking 2019 `memchr' for example, put it in `memchr.c' and use 2020 `AC_REPLACE_FUNCS(memchr)'. 2021 2022 - Macro: AC_HEADER_SYS_WAIT 2023 If `sys/wait.h' exists and is compatible with POSIX.1, define 2024 `HAVE_SYS_WAIT_H'. Incompatibility can occur if `sys/wait.h' does 2025 not exist, or if it uses the old BSD `union wait' instead of `int' 2026 to store a status value. If `sys/wait.h' is not POSIX.1 2027 compatible, then instead of including it, define the POSIX.1 2028 macros with their usual interpretations. Here is an example: 2029 2030 #include <sys/types.h> 2031 #if HAVE_SYS_WAIT_H 2032 # include <sys/wait.h> 2033 #endif 2034 #ifndef WEXITSTATUS 2035 # define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8) 2036 #endif 2037 #ifndef WIFEXITED 2038 # define WIFEXITED(stat_val) (((stat_val) & 255) == 0) 2039 #endif 2040 2041 - Macro: AC_MEMORY_H 2042 Define `NEED_MEMORY_H' if `memcpy', `memcmp', etc. are not 2043 declared in `string.h' and `memory.h' exists. This macro is 2044 obsolete; instead, use `AC_CHECK_HEADERS(memory.h)'. See the 2045 example for `AC_HEADER_STDC'. 2046 2047 - Macro: AC_UNISTD_H 2048 Define `HAVE_UNISTD_H' if the system has `unistd.h'. This macro 2049 is obsolete; instead, use `AC_CHECK_HEADERS(unistd.h)'. 2050 2051 The way to check if the system supports POSIX.1 is: 2052 2053 #if HAVE_UNISTD_H 2054 # include <sys/types.h> 2055 # include <unistd.h> 2056 #endif 2057 2058 #ifdef _POSIX_VERSION 2059 /* Code for POSIX.1 systems. */ 2060 #endif 2061 2062 `_POSIX_VERSION' is defined when `unistd.h' is included on POSIX.1 2063 systems. If there is no `unistd.h', it is definitely not a 2064 POSIX.1 system. However, some non-POSIX.1 systems do have 2065 `unistd.h'. 2066 2067 - Macro: AC_USG 2068 Define `USG' if the system does not have `strings.h', `rindex', 2069 `bzero', etc. This implies that it has `string.h', `strrchr', 2070 `memset', etc. 2071 2072 The symbol `USG' is obsolete. Instead of this macro, see the 2073 example for `AC_HEADER_STDC'. 2074 2075 2076File: autoconf.info, Node: Generic Headers, Prev: Particular Headers, Up: Header Files 2077 2078Generic Header Checks 2079--------------------- 2080 2081 These macros are used to find system header files not covered by the 2082particular test macros. If you need to check the contents of a header 2083as well as find out whether it is present, you have to write your own 2084test for it (*note Writing Tests::.). 2085 2086 - Macro: AC_CHECK_HEADER (HEADER-FILE, [ACTION-IF-FOUND [, 2087 ACTION-IF-NOT-FOUND]]) 2088 If the system header file HEADER-FILE exists, execute shell 2089 commands ACTION-IF-FOUND, otherwise execute ACTION-IF-NOT-FOUND. 2090 If you just want to define a symbol if the header file is 2091 available, consider using `AC_CHECK_HEADERS' instead. 2092 2093 - Macro: AC_CHECK_HEADERS (HEADER-FILE... [, ACTION-IF-FOUND [, 2094 ACTION-IF-NOT-FOUND]]) 2095 For each given system header file HEADER-FILE in the 2096 whitespace-separated argument list that exists, define 2097 `HAVE_HEADER-FILE' (in all capitals). If ACTION-IF-FOUND is 2098 given, it is additional shell code to execute when one of the 2099 header files is found. You can give it a value of `break' to 2100 break out of the loop on the first match. If ACTION-IF-NOT-FOUND 2101 is given, it is executed when one of the header files is not found. 2102 2103 2104File: autoconf.info, Node: Structures, Next: Typedefs, Prev: Header Files, Up: Existing Tests 2105 2106Structures 2107========== 2108 2109 The following macros check for certain structures or structure 2110members. To check structures not listed here, use `AC_EGREP_CPP' 2111(*note Examining Declarations::.) or `AC_TRY_COMPILE' (*note Examining 2112Syntax::.). 2113 2114 - Macro: AC_HEADER_STAT 2115 If the macros `S_ISDIR', `S_ISREG' et al. defined in `sys/stat.h' 2116 do not work properly (returning false positives), define 2117 `STAT_MACROS_BROKEN'. This is the case on Tektronix UTekV, Amdahl 2118 UTS and Motorola System V/88. 2119 2120 - Macro: AC_HEADER_TIME 2121 If a program may include both `time.h' and `sys/time.h', define 2122 `TIME_WITH_SYS_TIME'. On some older systems, `sys/time.h' 2123 includes `time.h', but `time.h' is not protected against multiple 2124 inclusion, so programs should not explicitly include both files. 2125 This macro is useful in programs that use, for example, `struct 2126 timeval' or `struct timezone' as well as `struct tm'. It is best 2127 used in conjunction with `HAVE_SYS_TIME_H', which can be checked 2128 for using `AC_CHECK_HEADERS(sys/time.h)'. 2129 2130 #if TIME_WITH_SYS_TIME 2131 # include <sys/time.h> 2132 # include <time.h> 2133 #else 2134 # if HAVE_SYS_TIME_H 2135 # include <sys/time.h> 2136 # else 2137 # include <time.h> 2138 # endif 2139 #endif 2140 2141 - Macro: AC_STRUCT_ST_BLKSIZE 2142 If `struct stat' contains an `st_blksize' member, define 2143 `HAVE_ST_BLKSIZE'. 2144 2145 - Macro: AC_STRUCT_ST_BLOCKS 2146 If `struct stat' contains an `st_blocks' member, define 2147 `HAVE_ST_BLOCKS'. Otherwise, add `fileblocks.o' to the output 2148 variable `LIBOBJS'. 2149 2150 - Macro: AC_STRUCT_ST_RDEV 2151 If `struct stat' contains an `st_rdev' member, define 2152 `HAVE_ST_RDEV'. 2153 2154 - Macro: AC_STRUCT_TM 2155 If `time.h' does not define `struct tm', define `TM_IN_SYS_TIME', 2156 which means that including `sys/time.h' had better define `struct 2157 tm'. 2158 2159 - Macro: AC_STRUCT_TIMEZONE 2160 Figure out how to get the current timezone. If `struct tm' has a 2161 `tm_zone' member, define `HAVE_TM_ZONE'. Otherwise, if the 2162 external array `tzname' is found, define `HAVE_TZNAME'. 2163 2164 2165File: autoconf.info, Node: Typedefs, Next: C Compiler Characteristics, Prev: Structures, Up: Existing Tests 2166 2167Typedefs 2168======== 2169 2170 The following macros check for C typedefs. If there is no macro 2171specifically defined to check for a typedef you need, and you don't need 2172to check for any special properties of it, then you can use a general 2173typedef check macro. 2174 2175* Menu: 2176 2177* Particular Typedefs:: Special handling to find certain types. 2178* Generic Typedefs:: How to find other types. 2179 2180 2181File: autoconf.info, Node: Particular Typedefs, Next: Generic Typedefs, Prev: Typedefs, Up: Typedefs 2182 2183Particular Typedef Checks 2184------------------------- 2185 2186 These macros check for particular C typedefs in `sys/types.h' and 2187`stdlib.h' (if it exists). 2188 2189 - Macro: AC_TYPE_GETGROUPS 2190 Define `GETGROUPS_T' to be whichever of `gid_t' or `int' is the 2191 base type of the array argument to `getgroups'. 2192 2193 - Macro: AC_TYPE_MODE_T 2194 If `mode_t' is not defined, define `mode_t' to be `int'. 2195 2196 - Macro: AC_TYPE_OFF_T 2197 If `off_t' is not defined, define `off_t' to be `long'. 2198 2199 - Macro: AC_TYPE_PID_T 2200 If `pid_t' is not defined, define `pid_t' to be `int'. 2201 2202 - Macro: AC_TYPE_SIGNAL 2203 If `signal.h' declares `signal' as returning a pointer to a 2204 function returning `void', define `RETSIGTYPE' to be `void'; 2205 otherwise, define it to be `int'. 2206 2207 Define signal handlers as returning type `RETSIGTYPE': 2208 2209 RETSIGTYPE 2210 hup_handler () 2211 { 2212 ... 2213 } 2214 2215 - Macro: AC_TYPE_SIZE_T 2216 If `size_t' is not defined, define `size_t' to be `unsigned'. 2217 2218 - Macro: AC_TYPE_UID_T 2219 If `uid_t' is not defined, define `uid_t' to be `int' and `gid_t' 2220 to be `int'. 2221 2222 2223File: autoconf.info, Node: Generic Typedefs, Prev: Particular Typedefs, Up: Typedefs 2224 2225Generic Typedef Checks 2226---------------------- 2227 2228 This macro is used to check for typedefs not covered by the 2229particular test macros. 2230 2231 - Macro: AC_CHECK_TYPE (TYPE, DEFAULT) 2232 If the type TYPE is not defined in `sys/types.h', or `stdlib.h' or 2233 `stddef.h' if they exist, define it to be the C (or C++) builtin 2234 type DEFAULT; e.g., `short' or `unsigned'. 2235 2236 2237File: autoconf.info, Node: C Compiler Characteristics, Next: Fortran 77 Compiler Characteristics, Prev: Typedefs, Up: Existing Tests 2238 2239C Compiler Characteristics 2240========================== 2241 2242 The following macros check for C compiler or machine architecture 2243features. To check for characteristics not listed here, use 2244`AC_TRY_COMPILE' (*note Examining Syntax::.) or `AC_TRY_RUN' (*note Run 2245Time::.) 2246 2247 - Macro: AC_C_BIGENDIAN 2248 If words are stored with the most significant byte first (like 2249 Motorola and SPARC, but not Intel and VAX, CPUs), define 2250 `WORDS_BIGENDIAN'. 2251 2252 - Macro: AC_C_CONST 2253 If the C compiler does not fully support the keyword `const', 2254 define `const' to be empty. Some C compilers that do not define 2255 `__STDC__' do support `const'; some compilers that define 2256 `__STDC__' do not completely support `const'. Programs can simply 2257 use `const' as if every C compiler supported it; for those that 2258 don't, the `Makefile' or configuration header file will define it 2259 as empty. 2260 2261 - Macro: AC_C_INLINE 2262 If the C compiler supports the keyword `inline', do nothing. 2263 Otherwise define `inline' to `__inline__' or `__inline' if it 2264 accepts one of those, otherwise define `inline' to be empty. 2265 2266 - Macro: AC_C_CHAR_UNSIGNED 2267 If the C type `char' is unsigned, define `__CHAR_UNSIGNED__', 2268 unless the C compiler predefines it. 2269 2270 - Macro: AC_C_LONG_DOUBLE 2271 If the C compiler supports the `long double' type, define 2272 `HAVE_LONG_DOUBLE'. Some C compilers that do not define 2273 `__STDC__' do support the `long double' type; some compilers that 2274 define `__STDC__' do not support `long double'. 2275 2276 - Macro: AC_C_STRINGIZE 2277 If the C preprocessor supports the stringizing operator, define 2278 `HAVE_STRINGIZE'. The stringizing operator is `#' and is found in 2279 macros such as this: 2280 2281 #define x(y) #y 2282 2283 - Macro: AC_CHECK_SIZEOF (TYPE [, CROSS-SIZE]) 2284 Define `SIZEOF_UCTYPE' to be the size in bytes of the C (or C++) 2285 builtin type TYPE, e.g. `int' or `char *'. If `type' is unknown 2286 to the compiler, it gets a size of 0. UCTYPE is TYPE, with 2287 lowercase converted to uppercase, spaces changed to underscores, 2288 and asterisks changed to `P'. If cross-compiling, the value 2289 CROSS-SIZE is used if given, otherwise `configure' exits with an 2290 error message. 2291 2292 For example, the call 2293 AC_CHECK_SIZEOF(int *) 2294 2295 defines `SIZEOF_INT_P' to be 8 on DEC Alpha AXP systems. 2296 2297 - Macro: AC_INT_16_BITS 2298 If the C type `int' is 16 bits wide, define `INT_16_BITS'. This 2299 macro is obsolete; it is more general to use 2300 `AC_CHECK_SIZEOF(int)' instead. 2301 2302 - Macro: AC_LONG_64_BITS 2303 If the C type `long int' is 64 bits wide, define `LONG_64_BITS'. 2304 This macro is obsolete; it is more general to use 2305 `AC_CHECK_SIZEOF(long)' instead. 2306 2307 2308File: autoconf.info, Node: Fortran 77 Compiler Characteristics, Next: System Services, Prev: C Compiler Characteristics, Up: Existing Tests 2309 2310Fortran 77 Compiler Characteristics 2311=================================== 2312 2313 The following macros check for Fortran 77 compiler characteristics. 2314To check for characteristics not listed here, use `AC_TRY_COMPILE' 2315(*note Examining Syntax::.) or `AC_TRY_RUN' (*note Run Time::.), making 2316sure to first set the current lanuage to Fortran 77 `AC_LANG_FORTRAN77' 2317(*note Language Choice::.). 2318 2319 - Macro: AC_F77_LIBRARY_LDFLAGS 2320 Determine the linker flags (e.g. `-L' and `-l') for the "Fortran 2321 77 intrinsic and run-time libraries" that are required to 2322 successfully link a Fortran 77 program or shared library. The 2323 output variable `FLIBS' is set to these flags. 2324 2325 This macro is intended to be used in those situations when it is 2326 necessary to mix, e.g. C++ and Fortran 77 source code into a single 2327 program or shared library (*note Mixing Fortran 77 With C and C++: 2328 (automake)Mixing Fortran 77 With C and C++.). 2329 2330 For example, if object files from a C++ and Fortran 77 compiler 2331 must be linked together, then the C++ compiler/linker must be used 2332 for linking (since special C++-ish things need to happen at link 2333 time like calling global constructors, instantiating templates, 2334 enabling exception support, etc.). 2335 2336 However, the Fortran 77 intrinsic and run-time libraries must be 2337 linked in as well, but the C++ compiler/linker doesn't know by 2338 default how to add these Fortran 77 libraries. Hence, the macro 2339 `AC_F77_LIBRARY_LDFLAGS' was created to determine these Fortran 77 2340 libraries. 2341 2342 2343File: autoconf.info, Node: System Services, Next: UNIX Variants, Prev: Fortran 77 Compiler Characteristics, Up: Existing Tests 2344 2345System Services 2346=============== 2347 2348 The following macros check for operating system services or 2349capabilities. 2350 2351 - Macro: AC_CYGWIN 2352 Checks for the Cygwin environment. If present, sets shell variable 2353 `CYGWIN' to `yes'. If not present, sets `CYGWIN' to the empty 2354 string. 2355 2356 - Macro: AC_EXEEXT 2357 Defines substitute variable `EXEEXT' based on the output of the 2358 compiler, after .c, .o, and .obj files have been excluded. 2359 Typically set to empty string if Unix, `.exe' or `.EXE' if Win32. 2360 2361 - Macro: AC_OBJEXT 2362 Defines substitute variable `OBJEXT' based on the output of the 2363 compiler, after .c files have been excluded. Typically set to 2364 `.o' if Unix, `.obj' if Win32. 2365 2366 - Macro: AC_MINGW32 2367 Checks for the MingW32 compiler environment. If present, sets 2368 shell variable `MINGW32' to `yes'. If not present, sets `MINGW32' 2369 to the empty string. 2370 2371 - Macro: AC_PATH_X 2372 Try to locate the X Window System include files and libraries. If 2373 the user gave the command line options `--x-includes=DIR' and 2374 `--x-libraries=DIR', use those directories. If either or both 2375 were not given, get the missing values by running `xmkmf' on a 2376 trivial `Imakefile' and examining the `Makefile' that it produces. 2377 If that fails (such as if `xmkmf' is not present), look for them 2378 in several directories where they often reside. If either method 2379 is successful, set the shell variables `x_includes' and 2380 `x_libraries' to their locations, unless they are in directories 2381 the compiler searches by default. 2382 2383 If both methods fail, or the user gave the command line option 2384 `--without-x', set the shell variable `no_x' to `yes'; otherwise 2385 set it to the empty string. 2386 2387 - Macro: AC_PATH_XTRA 2388 An enhanced version of `AC_PATH_X'. It adds the C compiler flags 2389 that X needs to output variable `X_CFLAGS', and the X linker flags 2390 to `X_LIBS'. If X is not available, adds `-DX_DISPLAY_MISSING' to 2391 `X_CFLAGS'. 2392 2393 This macro also checks for special libraries that some systems 2394 need in order to compile X programs. It adds any that the system 2395 needs to output variable `X_EXTRA_LIBS'. And it checks for 2396 special X11R6 libraries that need to be linked with before 2397 `-lX11', and adds any found to the output variable `X_PRE_LIBS'. 2398 2399 2400 - Macro: AC_SYS_INTERPRETER 2401 Check whether the system supports starting scripts with a line of 2402 the form `#! /bin/csh' to select the interpreter to use for the 2403 script. After running this macro, shell code in `configure.in' 2404 can check the shell variable `interpval'; it will be set to `yes' 2405 if the system supports `#!', `no' if not. 2406 2407 - Macro: AC_SYS_LONG_FILE_NAMES 2408 If the system supports file names longer than 14 characters, define 2409 `HAVE_LONG_FILE_NAMES'. 2410 2411 - Macro: AC_SYS_RESTARTABLE_SYSCALLS 2412 If the system automatically restarts a system call that is 2413 interrupted by a signal, define `HAVE_RESTARTABLE_SYSCALLS'. 2414 2415 2416File: autoconf.info, Node: UNIX Variants, Prev: System Services, Up: Existing Tests 2417 2418UNIX Variants 2419============= 2420 2421 The following macros check for certain operating systems that need 2422special treatment for some programs, due to exceptional oddities in 2423their header files or libraries. These macros are warts; they will be 2424replaced by a more systematic approach, based on the functions they make 2425available or the environments they provide. 2426 2427 - Macro: AC_AIX 2428 If on AIX, define `_ALL_SOURCE'. Allows the use of some BSD 2429 functions. Should be called before any macros that run the C 2430 compiler. 2431 2432 - Macro: AC_DYNIX_SEQ 2433 If on Dynix/PTX (Sequent UNIX), add `-lseq' to output variable 2434 `LIBS'. This macro is obsolete; instead, use `AC_FUNC_GETMNTENT'. 2435 2436 - Macro: AC_IRIX_SUN 2437 If on IRIX (Silicon Graphics UNIX), add `-lsun' to output variable 2438 `LIBS'. This macro is obsolete. If you were using it to get 2439 `getmntent', use `AC_FUNC_GETMNTENT' instead. If you used it for 2440 the NIS versions of the password and group functions, use 2441 `AC_CHECK_LIB(sun, getpwnam)'. 2442 2443 - Macro: AC_ISC_POSIX 2444 If on a POSIXized ISC UNIX, define `_POSIX_SOURCE' and add 2445 `-posix' (for the GNU C compiler) or `-Xp' (for other C compilers) 2446 to output variable `CC'. This allows the use of POSIX facilities. 2447 Must be called after `AC_PROG_CC' and before any other macros 2448 that run the C compiler. 2449 2450 - Macro: AC_MINIX 2451 If on Minix, define `_MINIX' and `_POSIX_SOURCE' and define 2452 `_POSIX_1_SOURCE' to be 2. This allows the use of POSIX 2453 facilities. Should be called before any macros that run the C 2454 compiler. 2455 2456 - Macro: AC_SCO_INTL 2457 If on SCO UNIX, add `-lintl' to output variable `LIBS'. This 2458 macro is obsolete; instead, use `AC_FUNC_STRFTIME'. 2459 2460 - Macro: AC_XENIX_DIR 2461 If on Xenix, add `-lx' to output variable `LIBS'. Also, if 2462 `dirent.h' is being used, add `-ldir' to `LIBS'. This macro is 2463 obsolete; use `AC_HEADER_DIRENT' instead. 2464 2465 2466File: autoconf.info, Node: Writing Tests, Next: Results, Prev: Existing Tests, Up: Top 2467 2468Writing Tests 2469************* 2470 2471 If the existing feature tests don't do something you need, you have 2472to write new ones. These macros are the building blocks. They provide 2473ways for other macros to check whether various kinds of features are 2474available and report the results. 2475 2476 This chapter contains some suggestions and some of the reasons why 2477the existing tests are written the way they are. You can also learn a 2478lot about how to write Autoconf tests by looking at the existing ones. 2479If something goes wrong in one or more of the Autoconf tests, this 2480information can help you understand the assumptions behind them, which 2481might help you figure out how to best solve the problem. 2482 2483 These macros check the output of the C compiler system. They do not 2484cache the results of their tests for future use (*note Caching 2485Results::.), because they don't know enough about the information they 2486are checking for to generate a cache variable name. They also do not 2487print any messages, for the same reason. The checks for particular 2488kinds of C features call these macros and do cache their results and 2489print messages about what they're checking for. 2490 2491 When you write a feature test that could be applicable to more than 2492one software package, the best thing to do is encapsulate it in a new 2493macro. *Note Writing Macros::, for how to do that. 2494 2495* Menu: 2496 2497* Examining Declarations:: Detecting header files and declarations. 2498* Examining Syntax:: Detecting language syntax features. 2499* Examining Libraries:: Detecting functions and global variables. 2500* Run Time:: Testing for run-time features. 2501* Portable Shell:: Shell script portability pitfalls. 2502* Testing Values and Files:: Checking strings and files. 2503* Multiple Cases:: Tests for several possible values. 2504* Language Choice:: Selecting which language to use for testing. 2505 2506 2507File: autoconf.info, Node: Examining Declarations, Next: Examining Syntax, Prev: Writing Tests, Up: Writing Tests 2508 2509Examining Declarations 2510====================== 2511 2512 The macro `AC_TRY_CPP' is used to check whether particular header 2513files exist. You can check for one at a time, or more than one if you 2514need several header files to all exist for some purpose. 2515 2516 - Macro: AC_TRY_CPP (INCLUDES, [ACTION-IF-TRUE [, ACTION-IF-FALSE]]) 2517 INCLUDES is C or C++ `#include' statements and declarations, on 2518 which shell variable, backquote, and backslash substitutions are 2519 performed. (Actually, it can be any C program, but other 2520 statements are probably not useful.) If the preprocessor produces 2521 no error messages while processing it, run shell commands 2522 ACTION-IF-TRUE. Otherwise run shell commands ACTION-IF-FALSE. 2523 2524 This macro uses `CPPFLAGS', but not `CFLAGS', because `-g', `-O', 2525 etc. are not valid options to many C preprocessors. 2526 2527 Here is how to find out whether a header file contains a particular 2528declaration, such as a typedef, a structure, a structure member, or a 2529function. Use `AC_EGREP_HEADER' instead of running `grep' directly on 2530the header file; on some systems the symbol might be defined in another 2531header file that the file you are checking `#include's. 2532 2533 - Macro: AC_EGREP_HEADER (PATTERN, HEADER-FILE, ACTION-IF-FOUND [, 2534 ACTION-IF-NOT-FOUND]) 2535 If the output of running the preprocessor on the system header file 2536 HEADER-FILE matches the `egrep' regular expression PATTERN, 2537 execute shell commands ACTION-IF-FOUND, otherwise execute 2538 ACTION-IF-NOT-FOUND. 2539 2540 To check for C preprocessor symbols, either defined by header files 2541or predefined by the C preprocessor, use `AC_EGREP_CPP'. Here is an 2542example of the latter: 2543 2544 AC_EGREP_CPP(yes, 2545 [#ifdef _AIX 2546 yes 2547 #endif 2548 ], is_aix=yes, is_aix=no) 2549 2550 - Macro: AC_EGREP_CPP (PATTERN, PROGRAM, [ACTION-IF-FOUND [, 2551 ACTION-IF-NOT-FOUND]]) 2552 PROGRAM is the text of a C or C++ program, on which shell 2553 variable, backquote, and backslash substitutions are performed. 2554 If the output of running the preprocessor on PROGRAM matches the 2555 `egrep' regular expression PATTERN, execute shell commands 2556 ACTION-IF-FOUND, otherwise execute ACTION-IF-NOT-FOUND. 2557 2558 This macro calls `AC_PROG_CPP' or `AC_PROG_CXXCPP' (depending on 2559 which language is current, *note Language Choice::.), if it hasn't 2560 been called already. 2561 2562 2563File: autoconf.info, Node: Examining Syntax, Next: Examining Libraries, Prev: Examining Declarations, Up: Writing Tests 2564 2565Examining Syntax 2566================ 2567 2568 To check for a syntax feature of the C, C++ or Fortran 77 compiler, 2569such as whether it recognizes a certain keyword, use `AC_TRY_COMPILE' to 2570try to compile a small program that uses that feature. You can also use 2571it to check for structures and structure members that are not present on 2572all systems. 2573 2574 - Macro: AC_TRY_COMPILE (INCLUDES, FUNCTION-BODY, [ACTION-IF-FOUND [, 2575 ACTION-IF-NOT-FOUND]]) 2576 Create a C, C++ or Fortran 77 test program (depending on which 2577 language is current, *note Language Choice::.), to see whether a 2578 function whose body consists of FUNCTION-BODY can be compiled. 2579 2580 For C and C++, INCLUDES is any `#include' statements needed by the 2581 code in FUNCTION-BODY (INCLUDES will be ignored if the currently 2582 selected language is Fortran 77). This macro also uses `CFLAGS' 2583 or `CXXFLAGS' if either C or C++ is the currently selected 2584 language, as well as `CPPFLAGS', when compiling. If Fortran 77 is 2585 the currently selected language then `FFLAGS' will be used when 2586 compiling. 2587 2588 If the file compiles successfully, run shell commands 2589 ACTION-IF-FOUND, otherwise run ACTION-IF-NOT-FOUND. 2590 2591 This macro does not try to link; use `AC_TRY_LINK' if you need to 2592 do that (*note Examining Libraries::.). 2593 2594 2595File: autoconf.info, Node: Examining Libraries, Next: Run Time, Prev: Examining Syntax, Up: Writing Tests 2596 2597Examining Libraries 2598=================== 2599 2600 To check for a library, a function, or a global variable, Autoconf 2601`configure' scripts try to compile and link a small program that uses 2602it. This is unlike Metaconfig, which by default uses `nm' or `ar' on 2603the C library to try to figure out which functions are available. 2604Trying to link with the function is usually a more reliable approach 2605because it avoids dealing with the variations in the options and output 2606formats of `nm' and `ar' and in the location of the standard libraries. 2607It also allows configuring for cross-compilation or checking a 2608function's runtime behavior if needed. On the other hand, it can be 2609slower than scanning the libraries once. 2610 2611 A few systems have linkers that do not return a failure exit status 2612when there are unresolved functions in the link. This bug makes the 2613configuration scripts produced by Autoconf unusable on those systems. 2614However, some of them can be given options that make the exit status 2615correct. This is a problem that Autoconf does not currently handle 2616automatically. If users encounter this problem, they might be able to 2617solve it by setting `LDFLAGS' in the environment to pass whatever 2618options the linker needs (for example, `-Wl,-dn' on MIPS RISC/OS). 2619 2620 `AC_TRY_LINK' is used to compile test programs to test for functions 2621and global variables. It is also used by `AC_CHECK_LIB' to check for 2622libraries (*note Libraries::.), by adding the library being checked for 2623to `LIBS' temporarily and trying to link a small program. 2624 2625 - Macro: AC_TRY_LINK (INCLUDES, FUNCTION-BODY, [ACTION-IF-FOUND [, 2626 ACTION-IF-NOT-FOUND]]) 2627 Depending on the current language (*note Language Choice::.), 2628 create a test program to see whether a function whose body 2629 consists of FUNCTION-BODY can be compiled and linked. 2630 2631 For C and C++, INCLUDES is any `#include' statements needed by the 2632 code in FUNCTION-BODY (INCLUDES will be ignored if the currently 2633 selected language is Fortran 77). This macro also uses `CFLAGS' 2634 or `CXXFLAGS' if either C or C++ is the currently selected 2635 language, as well as `CPPFLAGS', when compiling. If Fortran 77 is 2636 the currently selected language then `FFLAGS' will be used when 2637 compiling. However, both `LDFLAGS' and `LIBS' will be used during 2638 linking in all cases. 2639 2640 If the file compiles and links successfully, run shell commands 2641 ACTION-IF-FOUND, otherwise run ACTION-IF-NOT-FOUND. 2642 2643 - Macro: AC_TRY_LINK_FUNC (FUNCTION, [ACTION-IF-FOUND [, 2644 ACTION-IF-NOT-FOUND]]) 2645 Depending on the current language (*note Language Choice::.), 2646 create a test program to see whether a program whose body consists 2647 of a prototype of and a call to FUNCTION can be compiled and 2648 linked. 2649 2650 If the file compiles and links successfully, run shell commands 2651 ACTION-IF-FOUND, otherwise run ACTION-IF-NOT-FOUND. 2652 2653 - Macro: AC_TRY_LINK_FUNC (FUNCTION, [ACTION-IF-FOUND [, 2654 ACTION-IF-NOT-FOUND]]) 2655 Attempt to compile and link a small program that links with 2656 FUNCTION. If the file compiles and links successfully, run shell 2657 commands ACTION-IF-FOUND, otherwise run ACTION-IF-NOT-FOUND. 2658 2659 - Macro: AC_COMPILE_CHECK (ECHO-TEXT, INCLUDES, FUNCTION-BODY, 2660 ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]) 2661 This is an obsolete version of `AC_TRY_LINK', with the addition 2662 that it prints `checking for ECHO-TEXT' to the standard output 2663 first, if ECHO-TEXT is non-empty. Use `AC_MSG_CHECKING' and 2664 `AC_MSG_RESULT' instead to print messages (*note Printing 2665 Messages::.). 2666 2667 2668File: autoconf.info, Node: Run Time, Next: Portable Shell, Prev: Examining Libraries, Up: Writing Tests 2669 2670Checking Run Time Behavior 2671========================== 2672 2673 Sometimes you need to find out how a system performs at run time, 2674such as whether a given function has a certain capability or bug. If 2675you can, make such checks when your program runs instead of when it is 2676configured. You can check for things like the machine's endianness when 2677your program initializes itself. 2678 2679 If you really need to test for a run-time behavior while configuring, 2680you can write a test program to determine the result, and compile and 2681run it using `AC_TRY_RUN'. Avoid running test programs if possible, 2682because using them prevents people from configuring your package for 2683cross-compiling. 2684 2685* Menu: 2686 2687* Test Programs:: Running test programs. 2688* Guidelines:: General rules for writing test programs. 2689* Test Functions:: Avoiding pitfalls in test programs. 2690 2691 2692File: autoconf.info, Node: Test Programs, Next: Guidelines, Prev: Run Time, Up: Run Time 2693 2694Running Test Programs 2695--------------------- 2696 2697 Use the following macro if you need to test run-time behavior of the 2698system while configuring. 2699 2700 - Macro: AC_TRY_RUN (PROGRAM, [ACTION-IF-TRUE [, ACTION-IF-FALSE [, 2701 ACTION-IF-CROSS-COMPILING]]]) 2702 PROGRAM is the text of a C program, on which shell variable and 2703 backquote substitutions are performed. If it compiles and links 2704 successfully and returns an exit status of 0 when executed, run 2705 shell commands ACTION-IF-TRUE. Otherwise run shell commands 2706 ACTION-IF-FALSE; the exit status of the program is available in 2707 the shell variable `$?'. This macro uses `CFLAGS' or `CXXFLAGS', 2708 `CPPFLAGS', `LDFLAGS', and `LIBS' when compiling. 2709 2710 If the C compiler being used does not produce executables that run 2711 on the system where `configure' is being run, then the test 2712 program is not run. If the optional shell commands 2713 ACTION-IF-CROSS-COMPILING are given, they are run instead. 2714 Otherwise, `configure' prints an error message and exits. 2715 2716 Try to provide a pessimistic default value to use when 2717cross-compiling makes run-time tests impossible. You do this by 2718passing the optional last argument to `AC_TRY_RUN'. `autoconf' prints 2719a warning message when creating `configure' each time it encounters a 2720call to `AC_TRY_RUN' with no ACTION-IF-CROSS-COMPILING argument given. 2721You may ignore the warning, though users will not be able to configure 2722your package for cross-compiling. A few of the macros distributed with 2723Autoconf produce this warning message. 2724 2725 To configure for cross-compiling you can also choose a value for 2726those parameters based on the canonical system name (*note Manual 2727Configuration::.). Alternatively, set up a test results cache file with 2728the correct values for the target system (*note Caching Results::.). 2729 2730 To provide a default for calls of `AC_TRY_RUN' that are embedded in 2731other macros, including a few of the ones that come with Autoconf, you 2732can call `AC_PROG_CC' before running them. Then, if the shell variable 2733`cross_compiling' is set to `yes', use an alternate method to get the 2734results instead of calling the macros. 2735 2736 - Macro: AC_C_CROSS 2737 This macro is obsolete; it does nothing. 2738 2739 2740File: autoconf.info, Node: Guidelines, Next: Test Functions, Prev: Test Programs, Up: Run Time 2741 2742Guidelines for Test Programs 2743---------------------------- 2744 2745 Test programs should not write anything to the standard output. They 2746should return 0 if the test succeeds, nonzero otherwise, so that success 2747can be distinguished easily from a core dump or other failure; 2748segmentation violations and other failures produce a nonzero exit 2749status. Test programs should `exit', not `return', from `main', 2750because on some systems (old Suns, at least) the argument to `return' 2751in `main' is ignored. 2752 2753 Test programs can use `#if' or `#ifdef' to check the values of 2754preprocessor macros defined by tests that have already run. For 2755example, if you call `AC_HEADER_STDC', then later on in `configure.in' 2756you can have a test program that includes an ANSI C header file 2757conditionally: 2758 2759 #if STDC_HEADERS 2760 # include <stdlib.h> 2761 #endif 2762 2763 If a test program needs to use or create a data file, give it a name 2764that starts with `conftest', such as `conftestdata'. The `configure' 2765script cleans up by running `rm -rf conftest*' after running test 2766programs and if the script is interrupted. 2767 2768 2769File: autoconf.info, Node: Test Functions, Prev: Guidelines, Up: Run Time 2770 2771Test Functions 2772-------------- 2773 2774 Function declarations in test programs should have a prototype 2775conditionalized for C++. In practice, though, test programs rarely need 2776functions that take arguments. 2777 2778 #ifdef __cplusplus 2779 foo(int i) 2780 #else 2781 foo(i) int i; 2782 #endif 2783 2784 Functions that test programs declare should also be conditionalized 2785for C++, which requires `extern "C"' prototypes. Make sure to not 2786include any header files containing clashing prototypes. 2787 2788 #ifdef __cplusplus 2789 extern "C" void *malloc(size_t); 2790 #else 2791 char *malloc(); 2792 #endif 2793 2794 If a test program calls a function with invalid parameters (just to 2795see whether it exists), organize the program to ensure that it never 2796invokes that function. You can do this by calling it in another 2797function that is never invoked. You can't do it by putting it after a 2798call to `exit', because GCC version 2 knows that `exit' never returns 2799and optimizes out any code that follows it in the same block. 2800 2801 If you include any header files, make sure to call the functions 2802relevant to them with the correct number of arguments, even if they are 2803just 0, to avoid compilation errors due to prototypes. GCC version 2 2804has internal prototypes for several functions that it automatically 2805inlines; for example, `memcpy'. To avoid errors when checking for 2806them, either pass them the correct number of arguments or redeclare them 2807with a different return type (such as `char'). 2808 2809 2810File: autoconf.info, Node: Portable Shell, Next: Testing Values and Files, Prev: Run Time, Up: Writing Tests 2811 2812Portable Shell Programming 2813========================== 2814 2815 When writing your own checks, there are some shell script programming 2816techniques you should avoid in order to make your code portable. The 2817Bourne shell and upward-compatible shells like Bash and the Korn shell 2818have evolved over the years, but to prevent trouble, do not take 2819advantage of features that were added after UNIX version 7, circa 1977. 2820You should not use shell functions, aliases, negated character classes, 2821or other features that are not found in all Bourne-compatible shells; 2822restrict yourself to the lowest common denominator. Even `unset' is 2823not supported by all shells! Also, include a space after the 2824exclamation point in interpreter specifications, like this: 2825 #! /usr/bin/perl 2826 If you omit the space before the path, then 4.2BSD based systems 2827(such as Sequent DYNIX) will ignore the line, because they interpret 2828`#! /' as a 4-byte magic number. 2829 2830 The set of external programs you should run in a `configure' script 2831is fairly small. *Note Utilities in Makefiles: (standards)Utilities in 2832Makefiles, for the list. This restriction allows users to start out 2833with a fairly small set of programs and build the rest, avoiding too 2834many interdependencies between packages. 2835 2836 Some of these external utilities have a portable subset of features, 2837as well; for example, don't rely on `ln' having a `-f' option or `cat' 2838having any options. `sed' scripts should not contain comments or use 2839branch labels longer than 8 characters. Don't use `grep -s' to 2840suppress output, because `grep -s' on System V does not suppress 2841output, only error messages. Instead, redirect the standard output and 2842standard error (in case the file doesn't exist) of `grep' to 2843`/dev/null'. Check the exit status of `grep' to determine whether it 2844found a match. 2845 2846 2847File: autoconf.info, Node: Testing Values and Files, Next: Multiple Cases, Prev: Portable Shell, Up: Writing Tests 2848 2849Testing Values and Files 2850======================== 2851 2852 `configure' scripts need to test properties of many files and 2853strings. Here are some portability problems to watch out for when doing 2854those tests. 2855 2856 The `test' program is the way to perform many file and string tests. 2857It is often invoked by the alternate name `[', but using that name in 2858Autoconf code is asking for trouble since it is an `m4' quote character. 2859 2860 If you need to make multiple checks using `test', combine them with 2861the shell operators `&&' and `||' instead of using the `test' operators 2862`-a' and `-o'. On System V, the precedence of `-a' and `-o' is wrong 2863relative to the unary operators; consequently, POSIX does not specify 2864them, so using them is nonportable. If you combine `&&' and `||' in 2865the same statement, keep in mind that they have equal precedence. 2866 2867 To enable `configure' scripts to support cross-compilation, they 2868shouldn't do anything that tests features of the host system instead of 2869the target system. But occasionally you may find it necessary to check 2870whether some arbitrary file exists. To do so, use `test -f' or `test 2871-r'. Do not use `test -x', because 4.3BSD does not have it. 2872 2873 Another nonportable shell programming construction is 2874 VAR=${VAR:-VALUE} 2875 2876The intent is to set VAR to VALUE only if it is not already set, but if 2877VAR has any value, even the empty string, to leave it alone. Old BSD 2878shells, including the Ultrix `sh', don't accept the colon, and complain 2879and die. A portable equivalent is 2880 : ${VAR=VALUE} 2881 2882 2883File: autoconf.info, Node: Multiple Cases, Next: Language Choice, Prev: Testing Values and Files, Up: Writing Tests 2884 2885Multiple Cases 2886============== 2887 2888 Some operations are accomplished in several possible ways, depending 2889on the UNIX variant. Checking for them essentially requires a "case 2890statement". Autoconf does not directly provide one; however, it is 2891easy to simulate by using a shell variable to keep track of whether a 2892way to perform the operation has been found yet. 2893 2894 Here is an example that uses the shell variable `fstype' to keep 2895track of whether the remaining cases need to be checked. 2896 2897 AC_MSG_CHECKING(how to get filesystem type) 2898 fstype=no 2899 # The order of these tests is important. 2900 AC_TRY_CPP([#include <sys/statvfs.h> 2901 #include <sys/fstyp.h>], AC_DEFINE(FSTYPE_STATVFS) fstype=SVR4) 2902 if test $fstype = no; then 2903 AC_TRY_CPP([#include <sys/statfs.h> 2904 #include <sys/fstyp.h>], AC_DEFINE(FSTYPE_USG_STATFS) fstype=SVR3) 2905 fi 2906 if test $fstype = no; then 2907 AC_TRY_CPP([#include <sys/statfs.h> 2908 #include <sys/vmount.h>], AC_DEFINE(FSTYPE_AIX_STATFS) fstype=AIX) 2909 fi 2910 # (more cases omitted here) 2911 AC_MSG_RESULT($fstype) 2912 2913 2914File: autoconf.info, Node: Language Choice, Prev: Multiple Cases, Up: Writing Tests 2915 2916Language Choice 2917=============== 2918 2919 Packages that use both C and C++ need to test features of both 2920compilers. Autoconf-generated `configure' scripts check for C features 2921by default. The following macros determine which language's compiler 2922is used in tests that follow in `configure.in'. 2923 2924 - Macro: AC_LANG_C 2925 Do compilation tests using `CC' and `CPP' and use extension `.c' 2926 for test programs. Set the shell variable `cross_compiling' to 2927 the value computed by `AC_PROG_CC' if it has been run, empty 2928 otherwise. 2929 2930 - Macro: AC_LANG_CPLUSPLUS 2931 Do compilation tests using `CXX' and `CXXCPP' and use extension 2932 `.C' for test programs. Set the shell variable `cross_compiling' 2933 to the value computed by `AC_PROG_CXX' if it has been run, empty 2934 otherwise. 2935 2936 - Macro: AC_LANG_FORTRAN77 2937 Do compilation tests using `F77' and use extension `.f' for test 2938 programs. Set the shell variable `cross_compiling' to the value 2939 computed by `AC_PROG_F77' if it has been run, empty otherwise. 2940 2941 - Macro: AC_LANG_SAVE 2942 Remember the current language (as set by `AC_LANG_C', 2943 `AC_LANG_CPLUSPLUS' or `AC_LANG_FORTRAN77') on a stack. Does not 2944 change which language is current. Use this macro and 2945 `AC_LANG_RESTORE' in macros that need to temporarily switch to a 2946 particular language. 2947 2948 - Macro: AC_LANG_RESTORE 2949 Select the language that is saved on the top of the stack, as set 2950 by `AC_LANG_SAVE', and remove it from the stack. This macro is 2951 equivalent to either `AC_LANG_C', `AC_LANG_CPLUSPLUS' or 2952 `AC_LANG_FORTRAN77', whichever had been run most recently when 2953 `AC_LANG_SAVE' was last called. 2954 2955 Do not call this macro more times than `AC_LANG_SAVE'. 2956 2957 - Macro: AC_REQUIRE_CPP 2958 Ensure that whichever preprocessor would currently be used for 2959 tests has been found. Calls `AC_REQUIRE' (*note Prerequisite 2960 Macros::.) with an argument of either `AC_PROG_CPP' or 2961 `AC_PROG_CXXCPP', depending on which language is current. 2962 2963 2964File: autoconf.info, Node: Results, Next: Writing Macros, Prev: Writing Tests, Up: Top 2965 2966Results of Tests 2967**************** 2968 2969 Once `configure' has determined whether a feature exists, what can 2970it do to record that information? There are four sorts of things it can 2971do: define a C preprocessor symbol, set a variable in the output files, 2972save the result in a cache file for future `configure' runs, and print 2973a message letting the user know the result of the test. 2974 2975* Menu: 2976 2977* Defining Symbols:: Defining C preprocessor symbols. 2978* Setting Output Variables:: Replacing variables in output files. 2979* Caching Results:: Speeding up subsequent `configure' runs. 2980* Printing Messages:: Notifying users of progress or problems. 2981 2982 2983File: autoconf.info, Node: Defining Symbols, Next: Setting Output Variables, Prev: Results, Up: Results 2984 2985Defining C Preprocessor Symbols 2986=============================== 2987 2988 A common action to take in response to a feature test is to define a 2989C preprocessor symbol indicating the results of the test. That is done 2990by calling `AC_DEFINE' or `AC_DEFINE_UNQUOTED'. 2991 2992 By default, `AC_OUTPUT' places the symbols defined by these macros 2993into the output variable `DEFS', which contains an option 2994`-DSYMBOL=VALUE' for each symbol defined. Unlike in Autoconf version 29951, there is no variable `DEFS' defined while `configure' is running. 2996To check whether Autoconf macros have already defined a certain C 2997preprocessor symbol, test the value of the appropriate cache variable, 2998as in this example: 2999 3000 AC_CHECK_FUNC(vprintf, AC_DEFINE(HAVE_VPRINTF)) 3001 if test "$ac_cv_func_vprintf" != yes; then 3002 AC_CHECK_FUNC(_doprnt, AC_DEFINE(HAVE_DOPRNT)) 3003 fi 3004 3005 If `AC_CONFIG_HEADER' has been called, then instead of creating 3006`DEFS', `AC_OUTPUT' creates a header file by substituting the correct 3007values into `#define' statements in a template file. *Note 3008Configuration Headers::, for more information about this kind of output. 3009 3010 - Macro: AC_DEFINE (VARIABLE [, VALUE [, DESCRIPTION]]) 3011 Define C preprocessor variable VARIABLE. If VALUE is given, set 3012 VARIABLE to that value (verbatim), otherwise set it to 1. VALUE 3013 should not contain literal newlines, and if you are not using 3014 `AC_CONFIG_HEADER' it should not contain any `#' characters, as 3015 `make' tends to eat them. To use a shell variable (which you need 3016 to do in order to define a value containing the `m4' quote 3017 characters `[' or `]'), use `AC_DEFINE_UNQUOTED' instead. 3018 DESCRIPTION is only useful if you are using `AC_CONFIG_HEADER'. 3019 In this case, DESCRIPTION is put into the generated `config.h.in' 3020 as the comment before the macro define; the macro need not be 3021 mentioned in `acconfig.h'. The following example defines the C 3022 preprocessor variable `EQUATION' to be the string constant `"$a > 3023 $b"': 3024 3025 AC_DEFINE(EQUATION, "$a > $b") 3026 3027 - Macro: AC_DEFINE_UNQUOTED (VARIABLE [, VALUE [, DESCRIPTION]]) 3028 Like `AC_DEFINE', but three shell expansions are 3029 performed--once--on VARIABLE and VALUE: variable expansion (`$'), 3030 command substitution (``'), and backslash escaping (`\'). Single 3031 and double quote characters in the value have no special meaning. 3032 Use this macro instead of `AC_DEFINE' when VARIABLE or VALUE is a 3033 shell variable. Examples: 3034 3035 AC_DEFINE_UNQUOTED(config_machfile, "${machfile}") 3036 AC_DEFINE_UNQUOTED(GETGROUPS_T, $ac_cv_type_getgroups) 3037 AC_DEFINE_UNQUOTED(${ac_tr_hdr}) 3038 3039 Due to the syntactical bizarreness of the Bourne shell, do not use 3040semicolons to separate `AC_DEFINE' or `AC_DEFINE_UNQUOTED' calls from 3041other macro calls or shell code; that can cause syntax errors in the 3042resulting `configure' script. Use either spaces or newlines. That is, 3043do this: 3044 3045 AC_CHECK_HEADER(elf.h, AC_DEFINE(SVR4) LIBS="$LIBS -lelf") 3046 3047or this: 3048 3049 AC_CHECK_HEADER(elf.h, 3050 AC_DEFINE(SVR4) 3051 LIBS="$LIBS -lelf") 3052 3053instead of this: 3054 3055 AC_CHECK_HEADER(elf.h, AC_DEFINE(SVR4); LIBS="$LIBS -lelf") 3056 3057 3058File: autoconf.info, Node: Setting Output Variables, Next: Caching Results, Prev: Defining Symbols, Up: Results 3059 3060Setting Output Variables 3061======================== 3062 3063 One way to record the results of tests is to set "output variables", 3064which are shell variables whose values are substituted into files that 3065`configure' outputs. The two macros below create new output variables. 3066*Note Preset Output Variables::, for a list of output variables that 3067are always available. 3068 3069 - Macro: AC_SUBST (VARIABLE) 3070 Create an output variable from a shell variable. Make `AC_OUTPUT' 3071 substitute the variable VARIABLE into output files (typically one 3072 or more `Makefile's). This means that `AC_OUTPUT' will replace 3073 instances of `@VARIABLE@' in input files with the value that the 3074 shell variable VARIABLE has when `AC_OUTPUT' is called. The value 3075 of VARIABLE should not contain literal newlines. 3076 3077 - Macro: AC_SUBST_FILE (VARIABLE) 3078 Another way to create an output variable from a shell variable. 3079 Make `AC_OUTPUT' insert (without substitutions) the contents of 3080 the file named by shell variable VARIABLE into output files. This 3081 means that `AC_OUTPUT' will replace instances of `@VARIABLE@' in 3082 output files (such as `Makefile.in') with the contents of the file 3083 that the shell variable VARIABLE names when `AC_OUTPUT' is called. 3084 Set the variable to `/dev/null' for cases that do not have a file 3085 to insert. 3086 3087 This macro is useful for inserting `Makefile' fragments containing 3088 special dependencies or other `make' directives for particular host 3089 or target types into `Makefile's. For example, `configure.in' 3090 could contain: 3091 3092 AC_SUBST_FILE(host_frag)dnl 3093 host_frag=$srcdir/conf/sun4.mh 3094 3095 and then a `Makefile.in' could contain: 3096 3097 @host_frag@ 3098 3099 3100File: autoconf.info, Node: Caching Results, Next: Printing Messages, Prev: Setting Output Variables, Up: Results 3101 3102Caching Results 3103=============== 3104 3105 To avoid checking for the same features repeatedly in various 3106`configure' scripts (or repeated runs of one script), `configure' saves 3107the results of many of its checks in a "cache file". If, when a 3108`configure' script runs, it finds a cache file, it reads from it the 3109results from previous runs and avoids rerunning those checks. As a 3110result, `configure' can run much faster than if it had to perform all 3111of the checks every time. 3112 3113 - Macro: AC_CACHE_VAL (CACHE-ID, COMMANDS-TO-SET-IT) 3114 Ensure that the results of the check identified by CACHE-ID are 3115 available. If the results of the check were in the cache file 3116 that was read, and `configure' was not given the `--quiet' or 3117 `--silent' option, print a message saying that the result was 3118 cached; otherwise, run the shell commands COMMANDS-TO-SET-IT. 3119 Those commands should have no side effects except for setting the 3120 variable CACHE-ID. In particular, they should not call 3121 `AC_DEFINE'; the code that follows the call to `AC_CACHE_VAL' 3122 should do that, based on the cached value. Also, they should not 3123 print any messages, for example with `AC_MSG_CHECKING'; do that 3124 before calling `AC_CACHE_VAL', so the messages are printed 3125 regardless of whether the results of the check are retrieved from 3126 the cache or determined by running the shell commands. If the 3127 shell commands are run to determine the value, the value will be 3128 saved in the cache file just before `configure' creates its output 3129 files. *Note Cache Variable Names::, for how to choose the name 3130 of the CACHE-ID variable. 3131 3132 - Macro: AC_CACHE_CHECK (MESSAGE, CACHE-ID, COMMANDS) 3133 A wrapper for `AC_CACHE_VAL' that takes care of printing the 3134 messages. This macro provides a convenient shorthand for the most 3135 common way to use these macros. It calls `AC_MSG_CHECKING' for 3136 MESSAGE, then `AC_CACHE_VAL' with the CACHE-ID and COMMANDS 3137 arguments, and `AC_MSG_RESULT' with CACHE-ID. 3138 3139 - Macro: AC_CACHE_LOAD 3140 Loads values from existing cache file, or creates a new cache file 3141 if a cache file is not found. Called automatically from `AC_INIT'. 3142 3143 - Macro: AC_CACHE_SAVE 3144 Flushes all cached values to the cache file. Called automatically 3145 from `AC_OUTPUT', but it can be quite useful to call 3146 `AC_CACHE_SAVE' at key points in configure.in. Doing so 3147 checkpoints the cache in case of an early configure script abort. 3148 3149* Menu: 3150 3151* Cache Variable Names:: Shell variables used in caches. 3152* Cache Files:: Files `configure' uses for caching. 3153 3154 3155File: autoconf.info, Node: Cache Variable Names, Next: Cache Files, Prev: Caching Results, Up: Caching Results 3156 3157Cache Variable Names 3158-------------------- 3159 3160 The names of cache variables should have the following format: 3161 3162 PACKAGE-PREFIX_cv_VALUE-TYPE_SPECIFIC-VALUE[_ADDITIONAL-OPTIONS] 3163 3164for example, `ac_cv_header_stat_broken' or 3165`ac_cv_prog_gcc_traditional'. The parts of the variable name are: 3166 3167PACKAGE-PREFIX 3168 An abbreviation for your package or organization; the same prefix 3169 you begin local Autoconf macros with, except lowercase by 3170 convention. For cache values used by the distributed Autoconf 3171 macros, this value is `ac'. 3172 3173`_cv_' 3174 Indicates that this shell variable is a cache value. 3175 3176VALUE-TYPE 3177 A convention for classifying cache values, to produce a rational 3178 naming system. The values used in Autoconf are listed in *Note 3179 Macro Names::. 3180 3181SPECIFIC-VALUE 3182 Which member of the class of cache values this test applies to. 3183 For example, which function (`alloca'), program (`gcc'), or output 3184 variable (`INSTALL'). 3185 3186ADDITIONAL-OPTIONS 3187 Any particular behavior of the specific member that this test 3188 applies to. For example, `broken' or `set'. This part of the 3189 name may be omitted if it does not apply. 3190 3191 The values assigned to cache variables may not contain newlines. 3192Usually, their values will be boolean (`yes' or `no') or the names of 3193files or functions; so this is not an important restriction. 3194 3195 3196File: autoconf.info, Node: Cache Files, Prev: Cache Variable Names, Up: Caching Results 3197 3198Cache Files 3199----------- 3200 3201 A cache file is a shell script that caches the results of configure 3202tests run on one system so they can be shared between configure scripts 3203and configure runs. It is not useful on other systems. If its contents 3204are invalid for some reason, the user may delete or edit it. 3205 3206 By default, configure uses `./config.cache' as the cache file, 3207creating it if it does not exist already. `configure' accepts the 3208`--cache-file=FILE' option to use a different cache file; that is what 3209`configure' does when it calls `configure' scripts in subdirectories, 3210so they share the cache. *Note Subdirectories::, for information on 3211configuring subdirectories with the `AC_CONFIG_SUBDIRS' macro. 3212 3213 Giving `--cache-file=/dev/null' disables caching, for debugging 3214`configure'. `config.status' only pays attention to the cache file if 3215it is given the `--recheck' option, which makes it rerun `configure'. 3216If you are anticipating a long debugging period, you can also disable 3217cache loading and saving for a `configure' script by redefining the 3218cache macros at the start of `configure.in': 3219 3220 define([AC_CACHE_LOAD], )dnl 3221 define([AC_CACHE_SAVE], )dnl 3222 AC_INIT(whatever) 3223 ... rest of configure.in ... 3224 3225 It is wrong to try to distribute cache files for particular system 3226types. There is too much room for error in doing that, and too much 3227administrative overhead in maintaining them. For any features that 3228can't be guessed automatically, use the standard method of the canonical 3229system type and linking files (*note Manual Configuration::.). 3230 3231 The cache file on a particular system will gradually accumulate 3232whenever someone runs a `configure' script; it will be initially 3233nonexistent. Running `configure' merges the new cache results with the 3234existing cache file. The site initialization script can specify a 3235site-wide cache file to use instead of the default, to make it work 3236transparently, as long as the same C compiler is used every time (*note 3237Site Defaults::.). 3238 3239 If your configure script, or a macro called from configure.in, 3240happens to abort the configure process, it may be useful to checkpoint 3241the cache a few times at key points. Doing so will reduce the amount 3242of time it takes to re-run the configure script with (hopefully) the 3243error that caused the previous abort corrected. 3244 3245 ... AC_INIT, etc. ... 3246 dnl checks for programs 3247 AC_PROG_CC 3248 AC_PROG_GCC_TRADITIONAL 3249 ... more program checks ... 3250 AC_CACHE_SAVE 3251 3252 dnl checks for libraries 3253 AC_CHECK_LIB(nsl, gethostbyname) 3254 AC_CHECK_LIB(socket, connect) 3255 ... more lib checks ... 3256 AC_CACHE_SAVE 3257 3258 dnl Might abort... 3259 AM_PATH_GTK(1.0.2, , exit 1) 3260 AM_PATH_GTKMM(0.9.5, , exit 1) 3261 3262 3263File: autoconf.info, Node: Printing Messages, Prev: Caching Results, Up: Results 3264 3265Printing Messages 3266================= 3267 3268 `configure' scripts need to give users running them several kinds of 3269information. The following macros print messages in ways appropriate 3270for each kind. The arguments to all of them get enclosed in shell 3271double quotes, so the shell performs variable and backquote substitution 3272on them. You can print a message containing a comma by quoting the 3273message with the `m4' quote characters: 3274 3275 AC_MSG_RESULT([never mind, I found the BASIC compiler]) 3276 3277 These macros are all wrappers around the `echo' shell command. 3278`configure' scripts should rarely need to run `echo' directly to print 3279messages for the user. Using these macros makes it easy to change how 3280and when each kind of message is printed; such changes need only be 3281made to the macro definitions, and all of the callers change 3282automatically. 3283 3284 - Macro: AC_MSG_CHECKING (FEATURE-DESCRIPTION) 3285 Notify the user that `configure' is checking for a particular 3286 feature. This macro prints a message that starts with `checking ' 3287 and ends with `...' and no newline. It must be followed by a call 3288 to `AC_MSG_RESULT' to print the result of the check and the 3289 newline. The FEATURE-DESCRIPTION should be something like 3290 `whether the Fortran compiler accepts C++ comments' or `for c89'. 3291 3292 This macro prints nothing if `configure' is run with the `--quiet' 3293 or `--silent' option. 3294 3295 - Macro: AC_MSG_RESULT (RESULT-DESCRIPTION) 3296 Notify the user of the results of a check. RESULT-DESCRIPTION is 3297 almost always the value of the cache variable for the check, 3298 typically `yes', `no', or a file name. This macro should follow a 3299 call to `AC_MSG_CHECKING', and the RESULT-DESCRIPTION should be 3300 the completion of the message printed by the call to 3301 `AC_MSG_CHECKING'. 3302 3303 This macro prints nothing if `configure' is run with the `--quiet' 3304 or `--silent' option. 3305 3306 - Macro: AC_MSG_ERROR (ERROR-DESCRIPTION) 3307 Notify the user of an error that prevents `configure' from 3308 completing. This macro prints an error message on the standard 3309 error output and exits `configure' with a nonzero status. 3310 ERROR-DESCRIPTION should be something like `invalid value $HOME 3311 for \$HOME'. 3312 3313 - Macro: AC_MSG_WARN (PROBLEM-DESCRIPTION) 3314 Notify the `configure' user of a possible problem. This macro 3315 prints the message on the standard error output; `configure' 3316 continues running afterward, so macros that call `AC_MSG_WARN' 3317 should provide a default (back-up) behavior for the situations 3318 they warn about. PROBLEM-DESCRIPTION should be something like `ln 3319 -s seems to make hard links'. 3320 3321 The following two macros are an obsolete alternative to 3322`AC_MSG_CHECKING' and `AC_MSG_RESULT'. 3323 3324 - Macro: AC_CHECKING (FEATURE-DESCRIPTION) 3325 This macro is similar to `AC_MSG_CHECKING', except that it prints a 3326 newline after the FEATURE-DESCRIPTION. It is useful mainly to 3327 print a general description of the overall purpose of a group of 3328 feature checks, e.g., 3329 3330 AC_CHECKING(if stack overflow is detectable) 3331 3332 - Macro: AC_VERBOSE (RESULT-DESCRIPTION) 3333 This macro is similar to `AC_MSG_RESULT', except that it is meant 3334 to follow a call to `AC_CHECKING' instead of `AC_MSG_CHECKING'; it 3335 starts the message it prints with a tab. It is considered 3336 obsolete. 3337 3338 3339File: autoconf.info, Node: Writing Macros, Next: Manual Configuration, Prev: Results, Up: Top 3340 3341Writing Macros 3342************** 3343 3344 When you write a feature test that could be applicable to more than 3345one software package, the best thing to do is encapsulate it in a new 3346macro. Here are some instructions and guidelines for writing Autoconf 3347macros. 3348 3349* Menu: 3350 3351* Macro Definitions:: Basic format of an Autoconf macro. 3352* Macro Names:: What to call your new macros. 3353* Quoting:: Protecting macros from unwanted expansion. 3354* Dependencies Between Macros:: What to do when macros depend on other macros. 3355 3356 3357File: autoconf.info, Node: Macro Definitions, Next: Macro Names, Prev: Writing Macros, Up: Writing Macros 3358 3359Macro Definitions 3360================= 3361 3362 Autoconf macros are defined using the `AC_DEFUN' macro, which is 3363similar to the `m4' builtin `define' macro. In addition to defining a 3364macro, `AC_DEFUN' adds to it some code which is used to constrain the 3365order in which macros are called (*note Prerequisite Macros::.). 3366 3367 An Autoconf macro definition looks like this: 3368 3369 AC_DEFUN(MACRO-NAME, [MACRO-BODY]) 3370 3371The square brackets here do not indicate optional text: they should 3372literally be present in the macro definition to avoid macro expansion 3373problems (*note Quoting::.). You can refer to any arguments passed to 3374the macro as `$1', `$2', etc. 3375 3376 To introduce comments in `m4', use the `m4' builtin `dnl'; it causes 3377`m4' to discard the text through the next newline. It is not needed 3378between macro definitions in `acsite.m4' and `aclocal.m4', because all 3379output is discarded until `AC_INIT' is called. 3380 3381 *Note How to define new macros: (m4.info)Definitions, for more 3382complete information on writing `m4' macros. 3383 3384 3385File: autoconf.info, Node: Macro Names, Next: Quoting, Prev: Macro Definitions, Up: Writing Macros 3386 3387Macro Names 3388=========== 3389 3390 All of the Autoconf macros have all-uppercase names starting with 3391`AC_' to prevent them from accidentally conflicting with other text. 3392All shell variables that they use for internal purposes have 3393mostly-lowercase names starting with `ac_'. To ensure that your macros 3394don't conflict with present or future Autoconf macros, you should 3395prefix your own macro names and any shell variables they use with some 3396other sequence. Possibilities include your initials, or an abbreviation 3397for the name of your organization or software package. 3398 3399 Most of the Autoconf macros' names follow a structured naming 3400convention that indicates the kind of feature check by the name. The 3401macro names consist of several words, separated by underscores, going 3402from most general to most specific. The names of their cache 3403variables use the same convention (*note Cache Variable Names::., for 3404more information on them). 3405 3406 The first word of the name after `AC_' usually tells the category of 3407feature being tested. Here are the categories used in Autoconf for 3408specific test macros, the kind of macro that you are more likely to 3409write. They are also used for cache variables, in all-lowercase. Use 3410them where applicable; where they're not, invent your own categories. 3411 3412`C' 3413 C language builtin features. 3414 3415`DECL' 3416 Declarations of C variables in header files. 3417 3418`FUNC' 3419 Functions in libraries. 3420 3421`GROUP' 3422 UNIX group owners of files. 3423 3424`HEADER' 3425 Header files. 3426 3427`LIB' 3428 C libraries. 3429 3430`PATH' 3431 The full path names to files, including programs. 3432 3433`PROG' 3434 The base names of programs. 3435 3436`STRUCT' 3437 Definitions of C structures in header files. 3438 3439`SYS' 3440 Operating system features. 3441 3442`TYPE' 3443 C builtin or declared types. 3444 3445`VAR' 3446 C variables in libraries. 3447 3448 After the category comes the name of the particular feature being 3449tested. Any further words in the macro name indicate particular aspects 3450of the feature. For example, `AC_FUNC_UTIME_NULL' checks the behavior 3451of the `utime' function when called with a `NULL' pointer. 3452 3453 A macro that is an internal subroutine of another macro should have a 3454name that starts with the name of that other macro, followed by one or 3455more words saying what the internal macro does. For example, 3456`AC_PATH_X' has internal macros `AC_PATH_X_XMKMF' and 3457`AC_PATH_X_DIRECT'. 3458 3459 3460File: autoconf.info, Node: Quoting, Next: Dependencies Between Macros, Prev: Macro Names, Up: Writing Macros 3461 3462Quoting 3463======= 3464 3465 Macros that are called by other macros are evaluated by `m4' several 3466times; each evaluation might require another layer of quotes to prevent 3467unwanted expansions of macros or `m4' builtins, such as `define' and 3468`$1'. Quotes are also required around macro arguments that contain 3469commas, since commas separate the arguments from each other. It's a 3470good idea to quote any macro arguments that contain newlines or calls 3471to other macros, as well. 3472 3473 Autoconf changes the `m4' quote characters from the default ``' and 3474`'' to `[' and `]', because many of the macros use ``' and `'', 3475mismatched. However, in a few places the macros need to use brackets 3476(usually in C program text or regular expressions). In those places, 3477they use the `m4' builtin command `changequote' to temporarily change 3478the quote characters to `<<' and `>>'. (Sometimes, if they don't need 3479to quote anything, they disable quoting entirely instead by setting the 3480quote characters to empty strings.) Here is an example: 3481 3482 AC_TRY_LINK( 3483 changequote(<<, >>)dnl 3484 <<#include <time.h> 3485 #ifndef tzname /* For SGI. */ 3486 extern char *tzname[]; /* RS6000 and others reject char **tzname. */ 3487 #endif>>, 3488 changequote([, ])dnl 3489 [atoi(*tzname);], ac_cv_var_tzname=yes, ac_cv_var_tzname=no) 3490 3491 When you create a `configure' script using newly written macros, 3492examine it carefully to check whether you need to add more quotes in 3493your macros. If one or more words have disappeared in the `m4' output, 3494you need more quotes. When in doubt, quote. 3495 3496 However, it's also possible to put on too many layers of quotes. If 3497this happens, the resulting `configure' script will contain unexpanded 3498macros. The `autoconf' program checks for this problem by doing `grep 3499AC_ configure'. 3500 3501 3502File: autoconf.info, Node: Dependencies Between Macros, Prev: Quoting, Up: Writing Macros 3503 3504Dependencies Between Macros 3505=========================== 3506 3507 Some Autoconf macros depend on other macros having been called first 3508in order to work correctly. Autoconf provides a way to ensure that 3509certain macros are called if needed and a way to warn the user if 3510macros are called in an order that might cause incorrect operation. 3511 3512* Menu: 3513 3514* Prerequisite Macros:: Ensuring required information. 3515* Suggested Ordering:: Warning about possible ordering problems. 3516* Obsolete Macros:: Warning about old ways of doing things. 3517 3518 3519File: autoconf.info, Node: Prerequisite Macros, Next: Suggested Ordering, Prev: Dependencies Between Macros, Up: Dependencies Between Macros 3520 3521Prerequisite Macros 3522------------------- 3523 3524 A macro that you write might need to use values that have previously 3525been computed by other macros. For example, `AC_DECL_YYTEXT' examines 3526the output of `flex' or `lex', so it depends on `AC_PROG_LEX' having 3527been called first to set the shell variable `LEX'. 3528 3529 Rather than forcing the user of the macros to keep track of the 3530dependencies between them, you can use the `AC_REQUIRE' macro to do it 3531automatically. `AC_REQUIRE' can ensure that a macro is only called if 3532it is needed, and only called once. 3533 3534 - Macro: AC_REQUIRE (MACRO-NAME) 3535 If the `m4' macro MACRO-NAME has not already been called, call it 3536 (without any arguments). Make sure to quote MACRO-NAME with 3537 square brackets. MACRO-NAME must have been defined using 3538 `AC_DEFUN' or else contain a call to `AC_PROVIDE' to indicate that 3539 it has been called. 3540 3541 An alternative to using `AC_DEFUN' is to use `define' and call 3542`AC_PROVIDE'. Because this technique does not prevent nested messages, 3543it is considered obsolete. 3544 3545 - Macro: AC_PROVIDE (THIS-MACRO-NAME) 3546 Record the fact that THIS-MACRO-NAME has been called. 3547 THIS-MACRO-NAME should be the name of the macro that is calling 3548 `AC_PROVIDE'. An easy way to get it is from the `m4' builtin 3549 variable `$0', like this: 3550 3551 AC_PROVIDE([$0]) 3552 3553 3554File: autoconf.info, Node: Suggested Ordering, Next: Obsolete Macros, Prev: Prerequisite Macros, Up: Dependencies Between Macros 3555 3556Suggested Ordering 3557------------------ 3558 3559 Some macros should be run before another macro if both are called, 3560but neither *requires* that the other be called. For example, a macro 3561that changes the behavior of the C compiler should be called before any 3562macros that run the C compiler. Many of these dependencies are noted in 3563the documentation. 3564 3565 Autoconf provides the `AC_BEFORE' macro to warn users when macros 3566with this kind of dependency appear out of order in a `configure.in' 3567file. The warning occurs when creating `configure' from 3568`configure.in', not when running `configure'. For example, 3569`AC_PROG_CPP' checks whether the C compiler can run the C preprocessor 3570when given the `-E' option. It should therefore be called after any 3571macros that change which C compiler is being used, such as 3572`AC_PROG_CC'. So `AC_PROG_CC' contains: 3573 3574 AC_BEFORE([$0], [AC_PROG_CPP])dnl 3575 3576This warns the user if a call to `AC_PROG_CPP' has already occurred 3577when `AC_PROG_CC' is called. 3578 3579 - Macro: AC_BEFORE (THIS-MACRO-NAME, CALLED-MACRO-NAME) 3580 Make `m4' print a warning message on the standard error output if 3581 CALLED-MACRO-NAME has already been called. THIS-MACRO-NAME should 3582 be the name of the macro that is calling `AC_BEFORE'. The macro 3583 CALLED-MACRO-NAME must have been defined using `AC_DEFUN' or else 3584 contain a call to `AC_PROVIDE' to indicate that it has been called. 3585 3586 3587File: autoconf.info, Node: Obsolete Macros, Prev: Suggested Ordering, Up: Dependencies Between Macros 3588 3589Obsolete Macros 3590--------------- 3591 3592 Configuration and portability technology has evolved over the years. 3593Often better ways of solving a particular problem are developed, or 3594ad-hoc approaches are systematized. This process has occurred in many 3595parts of Autoconf. One result is that some of the macros are now 3596considered "obsolete"; they still work, but are no longer considered 3597the best thing to do. Autoconf provides the `AC_OBSOLETE' macro to 3598warn users producing `configure' scripts when they use obsolete macros, 3599to encourage them to modernize. A sample call is: 3600 3601 AC_OBSOLETE([$0], [; use AC_CHECK_HEADERS(unistd.h) instead])dnl 3602 3603 - Macro: AC_OBSOLETE (THIS-MACRO-NAME [, SUGGESTION]) 3604 Make `m4' print a message on the standard error output warning that 3605 THIS-MACRO-NAME is obsolete, and giving the file and line number 3606 where it was called. THIS-MACRO-NAME should be the name of the 3607 macro that is calling `AC_OBSOLETE'. If SUGGESTION is given, it 3608 is printed at the end of the warning message; for example, it can 3609 be a suggestion for what to use instead of THIS-MACRO-NAME. 3610 3611 3612File: autoconf.info, Node: Manual Configuration, Next: Site Configuration, Prev: Writing Macros, Up: Top 3613 3614Manual Configuration 3615******************** 3616 3617 A few kinds of features can't be guessed automatically by running 3618test programs. For example, the details of the object file format, or 3619special options that need to be passed to the compiler or linker. You 3620can check for such features using ad-hoc means, such as having 3621`configure' check the output of the `uname' program, or looking for 3622libraries that are unique to particular systems. However, Autoconf 3623provides a uniform method for handling unguessable features. 3624 3625* Menu: 3626 3627* Specifying Names:: Specifying the system type. 3628* Canonicalizing:: Getting the canonical system type. 3629* System Type Variables:: Variables containing the system type. 3630* Using System Type:: What to do with the system type. 3631 3632 3633File: autoconf.info, Node: Specifying Names, Next: Canonicalizing, Prev: Manual Configuration, Up: Manual Configuration 3634 3635Specifying the System Type 3636========================== 3637 3638 Like other GNU `configure' scripts, Autoconf-generated `configure' 3639scripts can make decisions based on a canonical name for the system 3640type, which has the form: 3641 3642 CPU-COMPANY-SYSTEM 3643 3644 `configure' can usually guess the canonical name for the type of 3645system it's running on. To do so it runs a script called 3646`config.guess', which derives the name using the `uname' command or 3647symbols predefined by the C preprocessor. 3648 3649 Alternately, the user can specify the system type with command line 3650arguments to `configure'. Doing so is necessary when cross-compiling. 3651In the most complex case of cross-compiling, three system types are 3652involved. The options to specify them are: 3653 3654`--build=BUILD-TYPE' 3655 the type of system on which the package is being configured and 3656 compiled (rarely needed); 3657 3658`--host=HOST-TYPE' 3659 the type of system on which the package will run; 3660 3661`--target=TARGET-TYPE' 3662 the type of system for which any compiler tools in the package will 3663 produce code. 3664 3665If the user gives `configure' a non-option argument, it is used as the 3666default for the host, target, and build system types if the user does 3667not specify them explicitly with options. The target and build types 3668default to the host type if it is given and they are not. If you are 3669cross-compiling, you still have to specify the names of the cross-tools 3670you use, in particular the C compiler, on the `configure' command line, 3671e.g., 3672 3673 CC=m68k-coff-gcc configure --target=m68k-coff 3674 3675 `configure' recognizes short aliases for many system types; for 3676example, `decstation' can be given on the command line instead of 3677`mips-dec-ultrix4.2'. `configure' runs a script called `config.sub' to 3678canonicalize system type aliases. 3679 3680 3681File: autoconf.info, Node: Canonicalizing, Next: System Type Variables, Prev: Specifying Names, Up: Manual Configuration 3682 3683Getting the Canonical System Type 3684================================= 3685 3686 The following macros make the system type available to `configure' 3687scripts. They run the shell script `config.guess' to determine any 3688values for the host, target, and build types that they need and the user 3689did not specify on the command line. They run `config.sub' to 3690canonicalize any aliases the user gave. If you use these macros, you 3691must distribute those two shell scripts along with your source code. 3692*Note Output::, for information about the `AC_CONFIG_AUX_DIR' macro 3693which you can use to control which directory `configure' looks for 3694those scripts in. If you do not use either of these macros, 3695`configure' ignores any `--host', `--target', and `--build' options 3696given to it. 3697 3698 - Macro: AC_CANONICAL_SYSTEM 3699 Determine the system type and set output variables to the names of 3700 the canonical system types. *Note System Type Variables::, for 3701 details about the variables this macro sets. 3702 3703 - Macro: AC_CANONICAL_HOST 3704 Perform only the subset of `AC_CANONICAL_SYSTEM' relevant to the 3705 host type. This is all that is needed for programs that are not 3706 part of a compiler toolchain. 3707 3708 - Macro: AC_VALIDATE_CACHED_SYSTEM_TUPLE (CMD) 3709 If the cache file is inconsistent with the current host, target 3710 and build system types, execute CMD or print a default error 3711 message. 3712 3713 3714File: autoconf.info, Node: System Type Variables, Next: Using System Type, Prev: Canonicalizing, Up: Manual Configuration 3715 3716System Type Variables 3717===================== 3718 3719 After calling `AC_CANONICAL_SYSTEM', the following output variables 3720contain the system type information. After `AC_CANONICAL_HOST', only 3721the `host' variables below are set. 3722 3723``build', `host', `target'' 3724 the canonical system names; 3725 3726``build_alias', `host_alias', `target_alias'' 3727 the names the user specified, or the canonical names if 3728 `config.guess' was used; 3729 3730``build_cpu', `build_vendor', `build_os'' 3731``host_cpu', `host_vendor', `host_os'' 3732``target_cpu', `target_vendor', `target_os'' 3733 the individual parts of the canonical names (for convenience). 3734 3735 3736File: autoconf.info, Node: Using System Type, Prev: System Type Variables, Up: Manual Configuration 3737 3738Using the System Type 3739===================== 3740 3741 How do you use a canonical system type? Usually, you use it in one 3742or more `case' statements in `configure.in' to select system-specific C 3743files. Then link those files, which have names based on the system 3744name, to generic names, such as `host.h' or `target.c'. The `case' 3745statement patterns can use shell wildcards to group several cases 3746together, like in this fragment: 3747 3748 case "$target" in 3749 i386-*-mach* | i386-*-gnu*) obj_format=aout emulation=mach bfd_gas=yes ;; 3750 i960-*-bout) obj_format=bout ;; 3751 esac 3752 3753 - Macro: AC_LINK_FILES (SOURCE..., DEST...) 3754 Make `AC_OUTPUT' link each of the existing files SOURCE to the 3755 corresponding link name DEST. Makes a symbolic link if possible, 3756 otherwise a hard link. The DEST and SOURCE names should be 3757 relative to the top level source or build directory. This macro 3758 may be called multiple times. 3759 3760 For example, this call: 3761 3762 AC_LINK_FILES(config/${machine}.h config/${obj_format}.h, host.h object.h) 3763 3764 creates in the current directory `host.h', which is a link to 3765 `SRCDIR/config/${machine}.h', and `object.h', which is a link to 3766 `SRCDIR/config/${obj_format}.h'. 3767 3768 You can also use the host system type to find cross-compilation 3769tools. *Note Generic Programs::, for information about the 3770`AC_CHECK_TOOL' macro which does that. 3771 3772 3773File: autoconf.info, Node: Site Configuration, Next: Invoking configure, Prev: Manual Configuration, Up: Top 3774 3775Site Configuration 3776****************** 3777 3778 `configure' scripts support several kinds of local configuration 3779decisions. There are ways for users to specify where external software 3780packages are, include or exclude optional features, install programs 3781under modified names, and set default values for `configure' options. 3782 3783* Menu: 3784 3785* External Software:: Working with other optional software. 3786* Package Options:: Selecting optional features. 3787* Site Details:: Configuring site details. 3788* Transforming Names:: Changing program names when installing. 3789* Site Defaults:: Giving `configure' local defaults. 3790 3791 3792File: autoconf.info, Node: External Software, Next: Package Options, Prev: Site Configuration, Up: Site Configuration 3793 3794Working With External Software 3795============================== 3796 3797 Some packages require, or can optionally use, other software packages 3798which are already installed. The user can give `configure' command 3799line options to specify which such external software to use. The 3800options have one of these forms: 3801 3802 --with-PACKAGE[=ARG] 3803 --without-PACKAGE 3804 3805 For example, `--with-gnu-ld' means work with the GNU linker instead 3806of some other linker. `--with-x' means work with The X Window System. 3807 3808 The user can give an argument by following the package name with `=' 3809and the argument. Giving an argument of `no' is for packages that are 3810used by default; it says to *not* use the package. An argument that is 3811neither `yes' nor `no' could include a name or number of a version of 3812the other package, to specify more precisely which other package this 3813program is supposed to work with. If no argument is given, it defaults 3814to `yes'. `--without-PACKAGE' is equivalent to `--with-PACKAGE=no'. 3815 3816 `configure' scripts do not complain about `--with-PACKAGE' options 3817that they do not support. This behavior permits configuring a source 3818tree containing multiple packages with a top-level `configure' script 3819when the packages support different options, without spurious error 3820messages about options that some of the packages support. An 3821unfortunate side effect is that option spelling errors are not 3822diagnosed. No better approach to this problem has been suggested so 3823far. 3824 3825 For each external software package that may be used, `configure.in' 3826should call `AC_ARG_WITH' to detect whether the `configure' user asked 3827to use it. Whether each package is used or not by default, and which 3828arguments are valid, is up to you. 3829 3830 - Macro: AC_ARG_WITH (PACKAGE, HELP-STRING [, ACTION-IF-GIVEN [, 3831 ACTION-IF-NOT-GIVEN]]) 3832 If the user gave `configure' the option `--with-PACKAGE' or 3833 `--without-PACKAGE', run shell commands ACTION-IF-GIVEN. If 3834 neither option was given, run shell commands ACTION-IF-NOT-GIVEN. 3835 The name PACKAGE indicates another software package that this 3836 program should work with. It should consist only of alphanumeric 3837 characters and dashes. 3838 3839 The option's argument is available to the shell commands 3840 ACTION-IF-GIVEN in the shell variable `withval', which is actually 3841 just the value of the shell variable `with_PACKAGE', with any `-' 3842 characters changed into `_'. You may use that variable instead, 3843 if you wish. 3844 3845 The argument HELP-STRING is a description of the option which 3846 looks like this: 3847 --with-readline support fancy command line editing 3848 3849 HELP-STRING may be more than one line long, if more detail is 3850 needed. Just make sure the columns line up in `configure --help'. 3851 Avoid tabs in the help string. You'll need to enclose it in `[' 3852 and `]' in order to produce the leading spaces. 3853 3854 - Macro: AC_WITH (PACKAGE, ACTION-IF-GIVEN [, ACTION-IF-NOT-GIVEN]) 3855 This is an obsolete version of `AC_ARG_WITH' that does not support 3856 providing a help string. 3857 3858 3859File: autoconf.info, Node: Package Options, Next: Site Details, Prev: External Software, Up: Site Configuration 3860 3861Choosing Package Options 3862======================== 3863 3864 If a software package has optional compile-time features, the user 3865can give `configure' command line options to specify whether to compile 3866them. The options have one of these forms: 3867 3868 --enable-FEATURE[=ARG] 3869 --disable-FEATURE 3870 3871 These options allow users to choose which optional features to build 3872and install. `--enable-FEATURE' options should never make a feature 3873behave differently or cause one feature to replace another. They 3874should only cause parts of the program to be built rather than left out. 3875 3876 The user can give an argument by following the feature name with `=' 3877and the argument. Giving an argument of `no' requests that the feature 3878*not* be made available. A feature with an argument looks like 3879`--enable-debug=stabs'. If no argument is given, it defaults to `yes'. 3880`--disable-FEATURE' is equivalent to `--enable-FEATURE=no'. 3881 3882 `configure' scripts do not complain about `--enable-FEATURE' options 3883that they do not support. This behavior permits configuring a source 3884tree containing multiple packages with a top-level `configure' script 3885when the packages support different options, without spurious error 3886messages about options that some of the packages support. An 3887unfortunate side effect is that option spelling errors are not 3888diagnosed. No better approach to this problem has been suggested so 3889far. 3890 3891 For each optional feature, `configure.in' should call 3892`AC_ARG_ENABLE' to detect whether the `configure' user asked to include 3893it. Whether each feature is included or not by default, and which 3894arguments are valid, is up to you. 3895 3896 - Macro: AC_ARG_ENABLE (FEATURE, HELP-STRING [, ACTION-IF-GIVEN [, 3897 ACTION-IF-NOT-GIVEN]]) 3898 If the user gave `configure' the option `--enable-FEATURE' or 3899 `--disable-FEATURE', run shell commands ACTION-IF-GIVEN. If 3900 neither option was given, run shell commands ACTION-IF-NOT-GIVEN. 3901 The name FEATURE indicates an optional user-level facility. It 3902 should consist only of alphanumeric characters and dashes. 3903 3904 The option's argument is available to the shell commands 3905 ACTION-IF-GIVEN in the shell variable `enableval', which is 3906 actually just the value of the shell variable `enable_FEATURE', 3907 with any `-' characters changed into `_'. You may use that 3908 variable instead, if you wish. The HELP-STRING argument is like 3909 that of `AC_ARG_WITH' (*note External Software::.). 3910 3911 - Macro: AC_ENABLE (FEATURE, ACTION-IF-GIVEN [, ACTION-IF-NOT-GIVEN]) 3912 This is an obsolete version of `AC_ARG_ENABLE' that does not 3913 support providing a help string. 3914 3915 3916File: autoconf.info, Node: Site Details, Next: Transforming Names, Prev: Package Options, Up: Site Configuration 3917 3918Configuring Site Details 3919======================== 3920 3921 Some software packages require complex site-specific information. 3922Some examples are host names to use for certain services, company 3923names, and email addresses to contact. Since some configuration 3924scripts generated by Metaconfig ask for such information interactively, 3925people sometimes wonder how to get that information in 3926Autoconf-generated configuration scripts, which aren't interactive. 3927 3928 Such site configuration information should be put in a file that is 3929edited *only by users*, not by programs. The location of the file can 3930either be based on the `prefix' variable, or be a standard location 3931such as the user's home directory. It could even be specified by an 3932environment variable. The programs should examine that file at run 3933time, rather than at compile time. Run time configuration is more 3934convenient for users and makes the configuration process simpler than 3935getting the information while configuring. *Note Variables for 3936Installation Directories: (standards)Directory Variables, for more 3937information on where to put data files. 3938 3939 3940File: autoconf.info, Node: Transforming Names, Next: Site Defaults, Prev: Site Details, Up: Site Configuration 3941 3942Transforming Program Names When Installing 3943========================================== 3944 3945 Autoconf supports changing the names of programs when installing 3946them. In order to use these transformations, `configure.in' must call 3947the macro `AC_ARG_PROGRAM'. 3948 3949 - Macro: AC_ARG_PROGRAM 3950 Place in output variable `program_transform_name' a sequence of 3951 `sed' commands for changing the names of installed programs. 3952 3953 If any of the options described below are given to `configure', 3954 program names are transformed accordingly. Otherwise, if 3955 `AC_CANONICAL_SYSTEM' has been called and a `--target' value is 3956 given that differs from the host type (specified with `--host' or 3957 defaulted by `config.sub'), the target type followed by a dash is 3958 used as a prefix. Otherwise, no program name transformation is 3959 done. 3960 3961* Menu: 3962 3963* Transformation Options:: `configure' options to transform names. 3964* Transformation Examples:: Sample uses of transforming names. 3965* Transformation Rules:: `Makefile' uses of transforming names. 3966 3967 3968File: autoconf.info, Node: Transformation Options, Next: Transformation Examples, Prev: Transforming Names, Up: Transforming Names 3969 3970Transformation Options 3971---------------------- 3972 3973 You can specify name transformations by giving `configure' these 3974command line options: 3975 3976`--program-prefix=PREFIX' 3977 prepend PREFIX to the names; 3978 3979`--program-suffix=SUFFIX' 3980 append SUFFIX to the names; 3981 3982`--program-transform-name=EXPRESSION' 3983 perform `sed' substitution EXPRESSION on the names. 3984 3985 3986File: autoconf.info, Node: Transformation Examples, Next: Transformation Rules, Prev: Transformation Options, Up: Transforming Names 3987 3988Transformation Examples 3989----------------------- 3990 3991 These transformations are useful with programs that can be part of a 3992cross-compilation development environment. For example, a 3993cross-assembler running on a Sun 4 configured with 3994`--target=i960-vxworks' is normally installed as `i960-vxworks-as', 3995rather than `as', which could be confused with a native Sun 4 assembler. 3996 3997 You can force a program name to begin with `g', if you don't want 3998GNU programs installed on your system to shadow other programs with the 3999same name. For example, if you configure GNU `diff' with 4000`--program-prefix=g', then when you run `make install' it is installed 4001as `/usr/local/bin/gdiff'. 4002 4003 As a more sophisticated example, you could use 4004 --program-transform-name='s/^/g/; s/^gg/g/; s/^gless/less/' 4005 4006to prepend `g' to most of the program names in a source tree, excepting 4007those like `gdb' that already have one and those like `less' and 4008`lesskey' that aren't GNU programs. (That is assuming that you have a 4009source tree containing those programs that is set up to use this 4010feature.) 4011 4012 One way to install multiple versions of some programs simultaneously 4013is to append a version number to the name of one or both. For example, 4014if you want to keep Autoconf version 1 around for awhile, you can 4015configure Autoconf version 2 using `--program-suffix=2' to install the 4016programs as `/usr/local/bin/autoconf2', `/usr/local/bin/autoheader2', 4017etc. 4018 4019 4020File: autoconf.info, Node: Transformation Rules, Prev: Transformation Examples, Up: Transforming Names 4021 4022Transformation Rules 4023-------------------- 4024 4025 Here is how to use the variable `program_transform_name' in a 4026`Makefile.in': 4027 4028 transform=@program_transform_name@ 4029 install: all 4030 $(INSTALL_PROGRAM) myprog $(bindir)/`echo myprog|sed '$(transform)'` 4031 4032 uninstall: 4033 rm -f $(bindir)/`echo myprog|sed '$(transform)'` 4034 4035If you have more than one program to install, you can do it in a loop: 4036 4037 PROGRAMS=cp ls rm 4038 install: 4039 for p in $(PROGRAMS); do \ 4040 $(INSTALL_PROGRAM) $$p $(bindir)/`echo $$p|sed '$(transform)'`; \ 4041 done 4042 4043 uninstall: 4044 for p in $(PROGRAMS); do \ 4045 rm -f $(bindir)/`echo $$p|sed '$(transform)'`; \ 4046 done 4047 4048 Whether to do the transformations on documentation files (Texinfo or 4049`man') is a tricky question; there seems to be no perfect answer, due 4050to the several reasons for name transforming. Documentation is not 4051usually particular to a specific architecture, and Texinfo files do not 4052conflict with system documentation. But they might conflict with 4053earlier versions of the same files, and `man' pages sometimes do 4054conflict with system documentation. As a compromise, it is probably 4055best to do name transformations on `man' pages but not on Texinfo 4056manuals. 4057 4058 4059File: autoconf.info, Node: Site Defaults, Prev: Transforming Names, Up: Site Configuration 4060 4061Setting Site Defaults 4062===================== 4063 4064 Autoconf-generated `configure' scripts allow your site to provide 4065default values for some configuration values. You do this by creating 4066site- and system-wide initialization files. 4067 4068 If the environment variable `CONFIG_SITE' is set, `configure' uses 4069its value as the name of a shell script to read. Otherwise, it reads 4070the shell script `PREFIX/share/config.site' if it exists, then 4071`PREFIX/etc/config.site' if it exists. Thus, settings in 4072machine-specific files override those in machine-independent ones in 4073case of conflict. 4074 4075 Site files can be arbitrary shell scripts, but only certain kinds of 4076code are really appropriate to be in them. Because `configure' reads 4077any cache file after it has read any site files, a site file can define 4078a default cache file to be shared between all Autoconf-generated 4079`configure' scripts run on that system. If you set a default cache 4080file in a site file, it is a good idea to also set the output variable 4081`CC' in that site file, because the cache file is only valid for a 4082particular compiler, but many systems have several available. 4083 4084 You can examine or override the value set by a command line option to 4085`configure' in a site file; options set shell variables that have the 4086same names as the options, with any dashes turned into underscores. 4087The exceptions are that `--without-' and `--disable-' options are like 4088giving the corresponding `--with-' or `--enable-' option and the value 4089`no'. Thus, `--cache-file=localcache' sets the variable `cache_file' 4090to the value `localcache'; `--enable-warnings=no' or 4091`--disable-warnings' sets the variable `enable_warnings' to the value 4092`no'; `--prefix=/usr' sets the variable `prefix' to the value `/usr'; 4093etc. 4094 4095 Site files are also good places to set default values for other 4096output variables, such as `CFLAGS', if you need to give them non-default 4097values: anything you would normally do, repetitively, on the command 4098line. If you use non-default values for PREFIX or EXEC_PREFIX 4099(wherever you locate the site file), you can set them in the site file 4100if you specify it with the `CONFIG_SITE' environment variable. 4101 4102 You can set some cache values in the site file itself. Doing this is 4103useful if you are cross-compiling, so it is impossible to check features 4104that require running a test program. You could "prime the cache" by 4105setting those values correctly for that system in 4106`PREFIX/etc/config.site'. To find out the names of the cache variables 4107you need to set, look for shell variables with `_cv_' in their names in 4108the affected `configure' scripts, or in the Autoconf `m4' source code 4109for those macros. 4110 4111 The cache file is careful to not override any variables set in the 4112site files. Similarly, you should not override command-line options in 4113the site files. Your code should check that variables such as `prefix' 4114and `cache_file' have their default values (as set near the top of 4115`configure') before changing them. 4116 4117 Here is a sample file `/usr/share/local/gnu/share/config.site'. The 4118command `configure --prefix=/usr/share/local/gnu' would read this file 4119(if `CONFIG_SITE' is not set to a different file). 4120 4121 # config.site for configure 4122 # 4123 # Change some defaults. 4124 test "$prefix" = NONE && prefix=/usr/share/local/gnu 4125 test "$exec_prefix" = NONE && exec_prefix=/usr/local/gnu 4126 test "$sharedstatedir" = '${prefix}/com' && sharedstatedir=/var 4127 test "$localstatedir" = '${prefix}/var' && localstatedir=/var 4128 # 4129 # Give Autoconf 2.x generated configure scripts a shared default 4130 # cache file for feature test results, architecture-specific. 4131 if test "$cache_file" = ./config.cache; then 4132 cache_file="$prefix/var/config.cache" 4133 # A cache file is only valid for one C compiler. 4134 CC=gcc 4135 fi 4136 4137 4138File: autoconf.info, Node: Invoking configure, Next: Invoking config.status, Prev: Site Configuration, Up: Top 4139 4140Running `configure' Scripts 4141*************************** 4142 4143 Below are instructions on how to configure a package that uses a 4144`configure' script, suitable for inclusion as an `INSTALL' file in the 4145package. A plain-text version of `INSTALL' which you may use comes 4146with Autoconf. 4147 4148* Menu: 4149 4150* Basic Installation:: Instructions for typical cases. 4151* Compilers and Options:: Selecting compilers and optimization. 4152* Multiple Architectures:: Compiling for multiple architectures at once. 4153* Installation Names:: Installing in different directories. 4154* Optional Features:: Selecting optional features. 4155* System Type:: Specifying the system type. 4156* Sharing Defaults:: Setting site-wide defaults for `configure'. 4157* Operation Controls:: Changing how `configure' runs. 4158 4159 4160File: autoconf.info, Node: Basic Installation, Next: Compilers and Options, Up: Invoking configure 4161 4162Basic Installation 4163================== 4164 4165 These are generic installation instructions. 4166 4167 The `configure' shell script attempts to guess correct values for 4168various system-dependent variables used during compilation. It uses 4169those values to create a `Makefile' in each directory of the package. 4170It may also create one or more `.h' files containing system-dependent 4171definitions. Finally, it creates a shell script `config.status' that 4172you can run in the future to recreate the current configuration, a file 4173`config.cache' that saves the results of its tests to speed up 4174reconfiguring, and a file `config.log' containing compiler output 4175(useful mainly for debugging `configure'). 4176 4177 If you need to do unusual things to compile the package, please try 4178to figure out how `configure' could check whether to do them, and mail 4179diffs or instructions to the address given in the `README' so they can 4180be considered for the next release. If at some point `config.cache' 4181contains results you don't want to keep, you may remove or edit it. 4182 4183 The file `configure.in' is used to create `configure' by a program 4184called `autoconf'. You only need `configure.in' if you want to change 4185it or regenerate `configure' using a newer version of `autoconf'. 4186 4187The simplest way to compile this package is: 4188 4189 1. `cd' to the directory containing the package's source code and type 4190 `./configure' to configure the package for your system. If you're 4191 using `csh' on an old version of System V, you might need to type 4192 `sh ./configure' instead to prevent `csh' from trying to execute 4193 `configure' itself. 4194 4195 Running `configure' takes awhile. While running, it prints some 4196 messages telling which features it is checking for. 4197 4198 2. Type `make' to compile the package. 4199 4200 3. Optionally, type `make check' to run any self-tests that come with 4201 the package. 4202 4203 4. Type `make install' to install the programs and any data files and 4204 documentation. 4205 4206 5. You can remove the program binaries and object files from the 4207 source code directory by typing `make clean'. To also remove the 4208 files that `configure' created (so you can compile the package for 4209 a different kind of computer), type `make distclean'. There is 4210 also a `make maintainer-clean' target, but that is intended mainly 4211 for the package's developers. If you use it, you may have to get 4212 all sorts of other programs in order to regenerate files that came 4213 with the distribution. 4214 4215 4216File: autoconf.info, Node: Compilers and Options, Next: Multiple Architectures, Prev: Basic Installation, Up: Invoking configure 4217 4218Compilers and Options 4219===================== 4220 4221 Some systems require unusual options for compilation or linking that 4222the `configure' script does not know about. You can give `configure' 4223initial values for variables by setting them in the environment. Using 4224a Bourne-compatible shell, you can do that on the command line like 4225this: 4226 CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure 4227 4228Or on systems that have the `env' program, you can do it like this: 4229 env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure 4230 4231 4232File: autoconf.info, Node: Multiple Architectures, Next: Installation Names, Prev: Compilers and Options, Up: Invoking configure 4233 4234Compiling For Multiple Architectures 4235==================================== 4236 4237 You can compile the package for more than one kind of computer at the 4238same time, by placing the object files for each architecture in their 4239own directory. To do this, you must use a version of `make' that 4240supports the `VPATH' variable, such as GNU `make'. `cd' to the 4241directory where you want the object files and executables to go and run 4242the `configure' script. `configure' automatically checks for the 4243source code in the directory that `configure' is in and in `..'. 4244 4245 If you have to use a `make' that does not supports the `VPATH' 4246variable, you have to compile the package for one architecture at a time 4247in the source code directory. After you have installed the package for 4248one architecture, use `make distclean' before reconfiguring for another 4249architecture. 4250 4251 4252File: autoconf.info, Node: Installation Names, Next: Optional Features, Prev: Multiple Architectures, Up: Invoking configure 4253 4254Installation Names 4255================== 4256 4257 By default, `make install' will install the package's files in 4258`/usr/local/bin', `/usr/local/man', etc. You can specify an 4259installation prefix other than `/usr/local' by giving `configure' the 4260option `--prefix=PATH'. 4261 4262 You can specify separate installation prefixes for 4263architecture-specific files and architecture-independent files. If you 4264give `configure' the option `--exec-prefix=PATH', the package will use 4265PATH as the prefix for installing programs and libraries. 4266Documentation and other data files will still use the regular prefix. 4267 4268 In addition, if you use an unusual directory layout you can give 4269options like `--bindir=PATH' to specify different values for particular 4270kinds of files. Run `configure --help' for a list of the directories 4271you can set and what kinds of files go in them. 4272 4273 If the package supports it, you can cause programs to be installed 4274with an extra prefix or suffix on their names by giving `configure' the 4275option `--program-prefix=PREFIX' or `--program-suffix=SUFFIX'. 4276 4277 4278File: autoconf.info, Node: Optional Features, Next: System Type, Prev: Installation Names, Up: Invoking configure 4279 4280Optional Features 4281================= 4282 4283 Some packages pay attention to `--enable-FEATURE' options to 4284`configure', where FEATURE indicates an optional part of the package. 4285They may also pay attention to `--with-PACKAGE' options, where PACKAGE 4286is something like `gnu-as' or `x' (for the X Window System). The 4287`README' should mention any `--enable-' and `--with-' options that the 4288package recognizes. 4289 4290 For packages that use the X Window System, `configure' can usually 4291find the X include and library files automatically, but if it doesn't, 4292you can use the `configure' options `--x-includes=DIR' and 4293`--x-libraries=DIR' to specify their locations. 4294 4295 4296File: autoconf.info, Node: System Type, Next: Sharing Defaults, Prev: Optional Features, Up: Invoking configure 4297 4298Specifying the System Type 4299========================== 4300 4301 There may be some features `configure' can not figure out 4302automatically, but needs to determine by the type of host the package 4303will run on. Usually `configure' can figure that out, but if it prints 4304a message saying it can not guess the host type, give it the 4305`--host=TYPE' option. TYPE can either be a short name for the system 4306type, such as `sun4', or a canonical name with three fields: 4307 CPU-COMPANY-SYSTEM 4308 4309See the file `config.sub' for the possible values of each field. If 4310`config.sub' isn't included in this package, then this package doesn't 4311need to know the host type. 4312 4313 If you are building compiler tools for cross-compiling, you can also 4314use the `--target=TYPE' option to select the type of system they will 4315produce code for and the `--build=TYPE' option to select the type of 4316system on which you are compiling the package. 4317 4318 4319File: autoconf.info, Node: Sharing Defaults, Next: Operation Controls, Prev: System Type, Up: Invoking configure 4320 4321Sharing Defaults 4322================ 4323 4324 If you want to set default values for `configure' scripts to share, 4325you can create a site shell script called `config.site' that gives 4326default values for variables like `CC', `cache_file', and `prefix'. 4327`configure' looks for `PREFIX/share/config.site' if it exists, then 4328`PREFIX/etc/config.site' if it exists. Or, you can set the 4329`CONFIG_SITE' environment variable to the location of the site script. 4330A warning: not all `configure' scripts look for a site script. 4331 4332 4333File: autoconf.info, Node: Operation Controls, Prev: Sharing Defaults, Up: Invoking configure 4334 4335Operation Controls 4336================== 4337 4338 `configure' recognizes the following options to control how it 4339operates. 4340 4341`--cache-file=FILE' 4342 Use and save the results of the tests in FILE instead of 4343 `./config.cache'. Set FILE to `/dev/null' to disable caching, for 4344 debugging `configure'. 4345 4346`--help' 4347 Print a summary of the options to `configure', and exit. 4348 4349`--quiet' 4350`--silent' 4351`-q' 4352 Do not print messages saying which checks are being made. To 4353 suppress all normal output, redirect it to `/dev/null' (any error 4354 messages will still be shown). 4355 4356`--srcdir=DIR' 4357 Look for the package's source code in directory DIR. Usually 4358 `configure' can determine that directory automatically. 4359 4360`--version' 4361 Print the version of Autoconf used to generate the `configure' 4362 script, and exit. 4363 4364`configure' also accepts some other, not widely useful, options. 4365 4366 4367File: autoconf.info, Node: Invoking config.status, Next: Questions, Prev: Invoking configure, Up: Top 4368 4369Recreating a Configuration 4370************************** 4371 4372 The `configure' script creates a file named `config.status' which 4373describes which configuration options were specified when the package 4374was last configured. This file is a shell script which, if run, will 4375recreate the same configuration. 4376 4377 You can give `config.status' the `--recheck' option to update 4378itself. This option is useful if you change `configure', so that the 4379results of some tests might be different from the previous run. The 4380`--recheck' option re-runs `configure' with the same arguments you used 4381before, plus the `--no-create' option, which prevent `configure' from 4382running `config.status' and creating `Makefile' and other files, and 4383the `--no-recursion' option, which prevents `configure' from running 4384other `configure' scripts in subdirectories. (This is so other 4385`Makefile' rules can run `config.status' when it changes; *note 4386Automatic Remaking::., for an example). 4387 4388 `config.status' also accepts the options `--help', which prints a 4389summary of the options to `config.status', and `--version', which 4390prints the version of Autoconf used to create the `configure' script 4391that generated `config.status'. 4392 4393 `config.status' checks several optional environment variables that 4394can alter its behavior: 4395 4396 - Variable: CONFIG_SHELL 4397 The shell with which to run `configure' for the `--recheck' 4398 option. It must be Bourne-compatible. The default is `/bin/sh'. 4399 4400 - Variable: CONFIG_STATUS 4401 The file name to use for the shell script that records the 4402 configuration. The default is `./config.status'. This variable is 4403 useful when one package uses parts of another and the `configure' 4404 scripts shouldn't be merged because they are maintained separately. 4405 4406 The following variables provide one way for separately distributed 4407packages to share the values computed by `configure'. Doing so can be 4408useful if some of the packages need a superset of the features that one 4409of them, perhaps a common library, does. These variables allow a 4410`config.status' file to create files other than the ones that its 4411`configure.in' specifies, so it can be used for a different package. 4412 4413 - Variable: CONFIG_FILES 4414 The files in which to perform `@VARIABLE@' substitutions. The 4415 default is the arguments given to `AC_OUTPUT' in `configure.in'. 4416 4417 - Variable: CONFIG_HEADERS 4418 The files in which to substitute C `#define' statements. The 4419 default is the arguments given to `AC_CONFIG_HEADER'; if that 4420 macro was not called, `config.status' ignores this variable. 4421 4422 These variables also allow you to write `Makefile' rules that 4423regenerate only some of the files. For example, in the dependencies 4424given above (*note Automatic Remaking::.), `config.status' is run twice 4425when `configure.in' has changed. If that bothers you, you can make 4426each run only regenerate the files for that rule: 4427 4428 config.h: stamp-h 4429 stamp-h: config.h.in config.status 4430 CONFIG_FILES= CONFIG_HEADERS=config.h ./config.status 4431 echo > stamp-h 4432 4433 Makefile: Makefile.in config.status 4434 CONFIG_FILES=Makefile CONFIG_HEADERS= ./config.status 4435 4436(If `configure.in' does not call `AC_CONFIG_HEADER', there is no need 4437to set `CONFIG_HEADERS' in the `make' rules.) 4438 4439 4440File: autoconf.info, Node: Questions, Next: Upgrading, Prev: Invoking config.status, Up: Top 4441 4442Questions About Autoconf 4443************************ 4444 4445 Several questions about Autoconf come up occasionally. Here some of 4446them are addressed. 4447 4448* Menu: 4449 4450* Distributing:: Distributing `configure' scripts. 4451* Why GNU m4:: Why not use the standard `m4'? 4452* Bootstrapping:: Autoconf and GNU `m4' require each other? 4453* Why Not Imake:: Why GNU uses `configure' instead of Imake. 4454 4455 4456File: autoconf.info, Node: Distributing, Next: Why GNU m4, Prev: Questions, Up: Questions 4457 4458Distributing `configure' Scripts 4459================================ 4460 4461 What are the restrictions on distributing `configure' 4462 scripts that Autoconf generates? How does that affect my 4463 programs that use them? 4464 4465 There are no restrictions on how the configuration scripts that 4466Autoconf produces may be distributed or used. In Autoconf version 1, 4467they were covered by the GNU General Public License. We still 4468encourage software authors to distribute their work under terms like 4469those of the GPL, but doing so is not required to use Autoconf. 4470 4471 Of the other files that might be used with `configure', 4472`config.h.in' is under whatever copyright you use for your 4473`configure.in', since it is derived from that file and from the public 4474domain file `acconfig.h'. `config.sub' and `config.guess' have an 4475exception to the GPL when they are used with an Autoconf-generated 4476`configure' script, which permits you to distribute them under the same 4477terms as the rest of your package. `install-sh' is from the X 4478Consortium and is not copyrighted. 4479 4480 4481File: autoconf.info, Node: Why GNU m4, Next: Bootstrapping, Prev: Distributing, Up: Questions 4482 4483Why Require GNU `m4'? 4484===================== 4485 4486 Why does Autoconf require GNU `m4'? 4487 4488 Many `m4' implementations have hard-coded limitations on the size 4489and number of macros, which Autoconf exceeds. They also lack several 4490builtin macros that it would be difficult to get along without in a 4491sophisticated application like Autoconf, including: 4492 4493 builtin 4494 indir 4495 patsubst 4496 __file__ 4497 __line__ 4498 4499 Since only software maintainers need to use Autoconf, and since GNU 4500`m4' is simple to configure and install, it seems reasonable to require 4501GNU `m4' to be installed also. Many maintainers of GNU and other free 4502software already have most of the GNU utilities installed, since they 4503prefer them. 4504 4505 4506File: autoconf.info, Node: Bootstrapping, Next: Why Not Imake, Prev: Why GNU m4, Up: Questions 4507 4508How Can I Bootstrap? 4509==================== 4510 4511 If Autoconf requires GNU `m4' and GNU `m4' has an 4512 Autoconf `configure' script, how do I bootstrap? It seems 4513 like a chicken and egg problem! 4514 4515 This is a misunderstanding. Although GNU `m4' does come with a 4516`configure' script produced by Autoconf, Autoconf is not required in 4517order to run the script and install GNU `m4'. Autoconf is only 4518required if you want to change the `m4' `configure' script, which few 4519people have to do (mainly its maintainer). 4520 4521 4522File: autoconf.info, Node: Why Not Imake, Prev: Bootstrapping, Up: Questions 4523 4524Why Not Imake? 4525============== 4526 4527 Why not use Imake instead of `configure' scripts? 4528 4529 Several people have written addressing this question, so I include 4530adaptations of their explanations here. 4531 4532 The following answer is based on one written by Richard Pixley: 4533 4534 Autoconf generated scripts frequently work on machines which it has 4535never been set up to handle before. That is, it does a good job of 4536inferring a configuration for a new system. Imake cannot do this. 4537 4538 Imake uses a common database of host specific data. For X11, this 4539makes sense because the distribution is made as a collection of tools, 4540by one central authority who has control over the database. 4541 4542 GNU tools are not released this way. Each GNU tool has a maintainer; 4543these maintainers are scattered across the world. Using a common 4544database would be a maintenance nightmare. Autoconf may appear to be 4545this kind of database, but in fact it is not. Instead of listing host 4546dependencies, it lists program requirements. 4547 4548 If you view the GNU suite as a collection of native tools, then the 4549problems are similar. But the GNU development tools can be configured 4550as cross tools in almost any host+target permutation. All of these 4551configurations can be installed concurrently. They can even be 4552configured to share host independent files across hosts. Imake doesn't 4553address these issues. 4554 4555 Imake templates are a form of standardization. The GNU coding 4556standards address the same issues without necessarily imposing the same 4557restrictions. 4558 4559 Here is some further explanation, written by Per Bothner: 4560 4561 One of the advantages of Imake is that it easy to generate large 4562Makefiles using `cpp''s `#include' and macro mechanisms. However, 4563`cpp' is not programmable: it has limited conditional facilities, and 4564no looping. And `cpp' cannot inspect its environment. 4565 4566 All of these problems are solved by using `sh' instead of `cpp'. 4567The shell is fully programmable, has macro substitution, can execute 4568(or source) other shell scripts, and can inspect its environment. 4569 4570 Paul Eggert elaborates more: 4571 4572 With Autoconf, installers need not assume that Imake itself is 4573already installed and working well. This may not seem like much of an 4574advantage to people who are accustomed to Imake. But on many hosts 4575Imake is not installed or the default installation is not working well, 4576and requiring Imake to install a package hinders the acceptance of that 4577package on those hosts. For example, the Imake template and 4578configuration files might not be installed properly on a host, or the 4579Imake build procedure might wrongly assume that all source files are in 4580one big directory tree, or the Imake configuration might assume one 4581compiler whereas the package or the installer needs to use another, or 4582there might be a version mismatch between the Imake expected by the 4583package and the Imake supported by the host. These problems are much 4584rarer with Autoconf, where each package comes with its own independent 4585configuration processor. 4586 4587 Also, Imake often suffers from unexpected interactions between 4588`make' and the installer's C preprocessor. The fundamental problem 4589here is that the C preprocessor was designed to preprocess C programs, 4590not `Makefile's. This is much less of a problem with Autoconf, which 4591uses the general-purpose preprocessor `m4', and where the package's 4592author (rather than the installer) does the preprocessing in a standard 4593way. 4594 4595 Finally, Mark Eichin notes: 4596 4597 Imake isn't all that extensible, either. In order to add new 4598features to Imake, you need to provide your own project template, and 4599duplicate most of the features of the existing one. This means that 4600for a sophisticated project, using the vendor-provided Imake templates 4601fails to provide any leverage--since they don't cover anything that 4602your own project needs (unless it is an X11 program). 4603 4604 On the other side, though: 4605 4606 The one advantage that Imake has over `configure': `Imakefile's tend 4607to be much shorter (likewise, less redundant) than `Makefile.in's. 4608There is a fix to this, however--at least for the Kerberos V5 tree, 4609we've modified things to call in common `post.in' and `pre.in' 4610`Makefile' fragments for the entire tree. This means that a lot of 4611common things don't have to be duplicated, even though they normally 4612are in `configure' setups. 4613 4614 4615File: autoconf.info, Node: Upgrading, Next: History, Prev: Questions, Up: Top 4616 4617Upgrading From Version 1 4618************************ 4619 4620 Autoconf version 2 is mostly backward compatible with version 1. 4621However, it introduces better ways to do some things, and doesn't 4622support some of the ugly things in version 1. So, depending on how 4623sophisticated your `configure.in' files are, you might have to do some 4624manual work in order to upgrade to version 2. This chapter points out 4625some problems to watch for when upgrading. Also, perhaps your 4626`configure' scripts could benefit from some of the new features in 4627version 2; the changes are summarized in the file `NEWS' in the 4628Autoconf distribution. 4629 4630 First, make sure you have GNU `m4' version 1.1 or higher installed, 4631preferably 1.3 or higher. Versions before 1.1 have bugs that prevent 4632them from working with Autoconf version 2. Versions 1.3 and later are 4633much faster than earlier versions, because as of version 1.3, GNU `m4' 4634has a more efficient implementation of diversions and can freeze its 4635internal state in a file that it can read back quickly. 4636 4637* Menu: 4638 4639* Changed File Names:: Files you might rename. 4640* Changed Makefiles:: New things to put in `Makefile.in'. 4641* Changed Macros:: Macro calls you might replace. 4642* Invoking autoupdate:: Replacing old macro names in `configure.in'. 4643* Changed Results:: Changes in how to check test results. 4644* Changed Macro Writing:: Better ways to write your own macros. 4645 4646 4647File: autoconf.info, Node: Changed File Names, Next: Changed Makefiles, Prev: Upgrading, Up: Upgrading 4648 4649Changed File Names 4650================== 4651 4652 If you have an `aclocal.m4' installed with Autoconf (as opposed to 4653in a particular package's source directory), you must rename it to 4654`acsite.m4'. *Note Invoking autoconf::. 4655 4656 If you distribute `install.sh' with your package, rename it to 4657`install-sh' so `make' builtin rules won't inadvertently create a file 4658called `install' from it. `AC_PROG_INSTALL' looks for the script under 4659both names, but it is best to use the new name. 4660 4661 If you were using `config.h.top' or `config.h.bot', you still can, 4662but you will have less clutter if you merge them into `acconfig.h'. 4663*Note Invoking autoheader::. 4664 4665 4666File: autoconf.info, Node: Changed Makefiles, Next: Changed Macros, Prev: Changed File Names, Up: Upgrading 4667 4668Changed Makefiles 4669================= 4670 4671 Add `@CFLAGS@', `@CPPFLAGS@', and `@LDFLAGS@' in your `Makefile.in' 4672files, so they can take advantage of the values of those variables in 4673the environment when `configure' is run. Doing this isn't necessary, 4674but it's a convenience for users. 4675 4676 Also add `@configure_input@' in a comment to each non-`Makefile' 4677input file for `AC_OUTPUT', so that the output files will contain a 4678comment saying they were produced by `configure'. Automatically 4679selecting the right comment syntax for all the kinds of files that 4680people call `AC_OUTPUT' on became too much work. 4681 4682 Add `config.log' and `config.cache' to the list of files you remove 4683in `distclean' targets. 4684 4685 If you have the following in `Makefile.in': 4686 4687 prefix = /usr/local 4688 exec_prefix = ${prefix} 4689 4690you must change it to: 4691 4692 prefix = @prefix@ 4693 exec_prefix = @exec_prefix@ 4694 4695The old behavior of replacing those variables without `@' characters 4696around them has been removed. 4697 4698 4699File: autoconf.info, Node: Changed Macros, Next: Invoking autoupdate, Prev: Changed Makefiles, Up: Upgrading 4700 4701Changed Macros 4702============== 4703 4704 Many of the macros were renamed in Autoconf version 2. You can still 4705use the old names, but the new ones are clearer, and it's easier to find 4706the documentation for them. *Note Old Macro Names::, for a table 4707showing the new names for the old macros. Use the `autoupdate' program 4708to convert your `configure.in' to using the new macro names. *Note 4709Invoking autoupdate::. 4710 4711 Some macros have been superseded by similar ones that do the job 4712better, but are not call-compatible. If you get warnings about calling 4713obsolete macros while running `autoconf', you may safely ignore them, 4714but your `configure' script will generally work better if you follow 4715the advice it prints about what to replace the obsolete macros with. In 4716particular, the mechanism for reporting the results of tests has 4717changed. If you were using `echo' or `AC_VERBOSE' (perhaps via 4718`AC_COMPILE_CHECK'), your `configure' script's output will look better 4719if you switch to `AC_MSG_CHECKING' and `AC_MSG_RESULT'. *Note Printing 4720Messages::. Those macros work best in conjunction with cache 4721variables. *Note Caching Results::. 4722 4723 4724File: autoconf.info, Node: Invoking autoupdate, Next: Changed Results, Prev: Changed Macros, Up: Upgrading 4725 4726Using `autoupdate' to Modernize `configure' 4727=========================================== 4728 4729 The `autoupdate' program updates a `configure.in' file that calls 4730Autoconf macros by their old names to use the current macro names. In 4731version 2 of Autoconf, most of the macros were renamed to use a more 4732uniform and descriptive naming scheme. *Note Macro Names::, for a 4733description of the new scheme. Although the old names still work 4734(*note Old Macro Names::., for a list of the old macro names and the 4735corresponding new names), you can make your `configure.in' files more 4736readable and make it easier to use the current Autoconf documentation 4737if you update them to use the new macro names. 4738 4739 If given no arguments, `autoupdate' updates `configure.in', backing 4740up the original version with the suffix `~' (or the value of the 4741environment variable `SIMPLE_BACKUP_SUFFIX', if that is set). If you 4742give `autoupdate' an argument, it reads that file instead of 4743`configure.in' and writes the updated file to the standard output. 4744 4745`autoupdate' accepts the following options: 4746 4747`--help' 4748`-h' 4749 Print a summary of the command line options and exit. 4750 4751`--macrodir=DIR' 4752`-m DIR' 4753 Look for the Autoconf macro files in directory DIR instead of the 4754 default installation directory. You can also set the `AC_MACRODIR' 4755 environment variable to a directory; this option overrides the 4756 environment variable. 4757 4758`--version' 4759 Print the version number of `autoupdate' and exit. 4760 4761 4762File: autoconf.info, Node: Changed Results, Next: Changed Macro Writing, Prev: Invoking autoupdate, Up: Upgrading 4763 4764Changed Results 4765=============== 4766 4767 If you were checking the results of previous tests by examining the 4768shell variable `DEFS', you need to switch to checking the values of the 4769cache variables for those tests. `DEFS' no longer exists while 4770`configure' is running; it is only created when generating output 4771files. This difference from version 1 is because properly quoting the 4772contents of that variable turned out to be too cumbersome and 4773inefficient to do every time `AC_DEFINE' is called. *Note Cache 4774Variable Names::. 4775 4776 For example, here is a `configure.in' fragment written for Autoconf 4777version 1: 4778 4779 AC_HAVE_FUNCS(syslog) 4780 case "$DEFS" in 4781 *-DHAVE_SYSLOG*) ;; 4782 *) # syslog is not in the default libraries. See if it's in some other. 4783 saved_LIBS="$LIBS" 4784 for lib in bsd socket inet; do 4785 AC_CHECKING(for syslog in -l$lib) 4786 LIBS="$saved_LIBS -l$lib" 4787 AC_HAVE_FUNCS(syslog) 4788 case "$DEFS" in 4789 *-DHAVE_SYSLOG*) break ;; 4790 *) ;; 4791 esac 4792 LIBS="$saved_LIBS" 4793 done ;; 4794 esac 4795 4796 Here is a way to write it for version 2: 4797 4798 AC_CHECK_FUNCS(syslog) 4799 if test $ac_cv_func_syslog = no; then 4800 # syslog is not in the default libraries. See if it's in some other. 4801 for lib in bsd socket inet; do 4802 AC_CHECK_LIB($lib, syslog, [AC_DEFINE(HAVE_SYSLOG) 4803 LIBS="$LIBS $lib"; break]) 4804 done 4805 fi 4806 4807 If you were working around bugs in `AC_DEFINE_UNQUOTED' by adding 4808backslashes before quotes, you need to remove them. It now works 4809predictably, and does not treat quotes (except backquotes) specially. 4810*Note Setting Output Variables::. 4811 4812 All of the boolean shell variables set by Autoconf macros now use 4813`yes' for the true value. Most of them use `no' for false, though for 4814backward compatibility some use the empty string instead. If you were 4815relying on a shell variable being set to something like 1 or `t' for 4816true, you need to change your tests. 4817 4818 4819File: autoconf.info, Node: Changed Macro Writing, Prev: Changed Results, Up: Upgrading 4820 4821Changed Macro Writing 4822===================== 4823 4824 When defining your own macros, you should now use `AC_DEFUN' instead 4825of `define'. `AC_DEFUN' automatically calls `AC_PROVIDE' and ensures 4826that macros called via `AC_REQUIRE' do not interrupt other macros, to 4827prevent nested `checking...' messages on the screen. There's no actual 4828harm in continuing to use the older way, but it's less convenient and 4829attractive. *Note Macro Definitions::. 4830 4831 You probably looked at the macros that came with Autoconf as a guide 4832for how to do things. It would be a good idea to take a look at the new 4833versions of them, as the style is somewhat improved and they take 4834advantage of some new features. 4835 4836 If you were doing tricky things with undocumented Autoconf internals 4837(macros, variables, diversions), check whether you need to change 4838anything to account for changes that have been made. Perhaps you can 4839even use an officially supported technique in version 2 instead of 4840kludging. Or perhaps not. 4841 4842 To speed up your locally written feature tests, add caching to them. 4843See whether any of your tests are of general enough usefulness to 4844encapsulate into macros that you can share. 4845 4846 4847File: autoconf.info, Node: History, Next: Old Macro Names, Prev: Upgrading, Up: Top 4848 4849History of Autoconf 4850******************* 4851 4852 You may be wondering, Why was Autoconf originally written? How did 4853it get into its present form? (Why does it look like gorilla spit?) If 4854you're not wondering, then this chapter contains no information useful 4855to you, and you might as well skip it. If you *are* wondering, then 4856let there be light... 4857 4858* Menu: 4859 4860* Genesis:: Prehistory and naming of `configure'. 4861* Exodus:: The plagues of `m4' and Perl. 4862* Leviticus:: The priestly code of portability arrives. 4863* Numbers:: Growth and contributors. 4864* Deuteronomy:: Approaching the promises of easy configuration. 4865 4866 4867File: autoconf.info, Node: Genesis, Next: Exodus, Prev: History, Up: History 4868 4869Genesis 4870======= 4871 4872 In June 1991 I was maintaining many of the GNU utilities for the Free 4873Software Foundation. As they were ported to more platforms and more 4874programs were added, the number of `-D' options that users had to 4875select in the `Makefile' (around 20) became burdensome. Especially for 4876me--I had to test each new release on a bunch of different systems. So 4877I wrote a little shell script to guess some of the correct settings for 4878the fileutils package, and released it as part of fileutils 2.0. That 4879`configure' script worked well enough that the next month I adapted it 4880(by hand) to create similar `configure' scripts for several other GNU 4881utilities packages. Brian Berliner also adapted one of my scripts for 4882his CVS revision control system. 4883 4884 Later that summer, I learned that Richard Stallman and Richard Pixley 4885were developing similar scripts to use in the GNU compiler tools; so I 4886adapted my `configure' scripts to support their evolving interface: 4887using the file name `Makefile.in' as the templates; adding `+srcdir', 4888the first option (of many); and creating `config.status' files. 4889 4890 4891File: autoconf.info, Node: Exodus, Next: Leviticus, Prev: Genesis, Up: History 4892 4893Exodus 4894====== 4895 4896 As I got feedback from users, I incorporated many improvements, using 4897Emacs to search and replace, cut and paste, similar changes in each of 4898the scripts. As I adapted more GNU utilities packages to use 4899`configure' scripts, updating them all by hand became impractical. 4900Rich Murphey, the maintainer of the GNU graphics utilities, sent me mail 4901saying that the `configure' scripts were great, and asking if I had a 4902tool for generating them that I could send him. No, I thought, but I 4903should! So I started to work out how to generate them. And the 4904journey from the slavery of hand-written `configure' scripts to the 4905abundance and ease of Autoconf began. 4906 4907 Cygnus `configure', which was being developed at around that time, 4908is table driven; it is meant to deal mainly with a discrete number of 4909system types with a small number of mainly unguessable features (such as 4910details of the object file format). The automatic configuration system 4911that Brian Fox had developed for Bash takes a similar approach. For 4912general use, it seems to me a hopeless cause to try to maintain an 4913up-to-date database of which features each variant of each operating 4914system has. It's easier and more reliable to check for most features on 4915the fly--especially on hybrid systems that people have hacked on 4916locally or that have patches from vendors installed. 4917 4918 I considered using an architecture similar to that of Cygnus 4919`configure', where there is a single `configure' script that reads 4920pieces of `configure.in' when run. But I didn't want to have to 4921distribute all of the feature tests with every package, so I settled on 4922having a different `configure' made from each `configure.in' by a 4923preprocessor. That approach also offered more control and flexibility. 4924 4925 I looked briefly into using the Metaconfig package, by Larry Wall, 4926Harlan Stenn, and Raphael Manfredi, but I decided not to for several 4927reasons. The `Configure' scripts it produces are interactive, which I 4928find quite inconvenient; I didn't like the ways it checked for some 4929features (such as library functions); I didn't know that it was still 4930being maintained, and the `Configure' scripts I had seen didn't work on 4931many modern systems (such as System V R4 and NeXT); it wasn't very 4932flexible in what it could do in response to a feature's presence or 4933absence; I found it confusing to learn; and it was too big and complex 4934for my needs (I didn't realize then how much Autoconf would eventually 4935have to grow). 4936 4937 I considered using Perl to generate my style of `configure' scripts, 4938but decided that `m4' was better suited to the job of simple textual 4939substitutions: it gets in the way less, because output is implicit. 4940Plus, everyone already has it. (Initially I didn't rely on the GNU 4941extensions to `m4'.) Also, some of my friends at the University of 4942Maryland had recently been putting `m4' front ends on several programs, 4943including `tvtwm', and I was interested in trying out a new language. 4944 4945 4946File: autoconf.info, Node: Leviticus, Next: Numbers, Prev: Exodus, Up: History 4947 4948Leviticus 4949========= 4950 4951 Since my `configure' scripts determine the system's capabilities 4952automatically, with no interactive user intervention, I decided to call 4953the program that generates them Autoconfig. But with a version number 4954tacked on, that name would be too long for old UNIX file systems, so I 4955shortened it to Autoconf. 4956 4957 In the fall of 1991 I called together a group of fellow questers 4958after the Holy Grail of portability (er, that is, alpha testers) to 4959give me feedback as I encapsulated pieces of my handwritten scripts in 4960`m4' macros and continued to add features and improve the techniques 4961used in the checks. Prominent among the testers were Franc,ois Pinard, 4962who came up with the idea of making an `autoconf' shell script to run 4963`m4' and check for unresolved macro calls; Richard Pixley, who 4964suggested running the compiler instead of searching the file system to 4965find include files and symbols, for more accurate results; Karl Berry, 4966who got Autoconf to configure TeX and added the macro index to the 4967documentation; and Ian Taylor, who added support for creating a C 4968header file as an alternative to putting `-D' options in a `Makefile', 4969so he could use Autoconf for his UUCP package. The alpha testers 4970cheerfully adjusted their files again and again as the names and 4971calling conventions of the Autoconf macros changed from release to 4972release. They all contributed many specific checks, great ideas, and 4973bug fixes. 4974 4975 4976File: autoconf.info, Node: Numbers, Next: Deuteronomy, Prev: Leviticus, Up: History 4977 4978Numbers 4979======= 4980 4981 In July 1992, after months of alpha testing, I released Autoconf 1.0, 4982and converted many GNU packages to use it. I was surprised by how 4983positive the reaction to it was. More people started using it than I 4984could keep track of, including people working on software that wasn't 4985part of the GNU Project (such as TCL, FSP, and Kerberos V5). Autoconf 4986continued to improve rapidly, as many people using the `configure' 4987scripts reported problems they encountered. 4988 4989 Autoconf turned out to be a good torture test for `m4' 4990implementations. UNIX `m4' started to dump core because of the length 4991of the macros that Autoconf defined, and several bugs showed up in GNU 4992`m4' as well. Eventually, we realized that we needed to use some 4993features that only GNU `m4' has. 4.3BSD `m4', in particular, has an 4994impoverished set of builtin macros; the System V version is better, but 4995still doesn't provide everything we need. 4996 4997 More development occurred as people put Autoconf under more stresses 4998(and to uses I hadn't anticipated). Karl Berry added checks for X11. 4999david zuhn contributed C++ support. Franc,ois Pinard made it diagnose 5000invalid arguments. Jim Blandy bravely coerced it into configuring GNU 5001Emacs, laying the groundwork for several later improvements. Roland 5002McGrath got it to configure the GNU C Library, wrote the `autoheader' 5003script to automate the creation of C header file templates, and added a 5004`--verbose' option to `configure'. Noah Friedman added the 5005`--macrodir' option and `AC_MACRODIR' environment variable. (He also 5006coined the term "autoconfiscate" to mean "adapt a software package to 5007use Autoconf".) Roland and Noah improved the quoting protection in 5008`AC_DEFINE' and fixed many bugs, especially when I got sick of dealing 5009with portability problems from February through June, 1993. 5010 5011 5012File: autoconf.info, Node: Deuteronomy, Prev: Numbers, Up: History 5013 5014Deuteronomy 5015=========== 5016 5017 A long wish list for major features had accumulated, and the effect 5018of several years of patching by various people had left some residual 5019cruft. In April 1994, while working for Cygnus Support, I began a major 5020revision of Autoconf. I added most of the features of the Cygnus 5021`configure' that Autoconf had lacked, largely by adapting the relevant 5022parts of Cygnus `configure' with the help of david zuhn and Ken 5023Raeburn. These features include support for using `config.sub', 5024`config.guess', `--host', and `--target'; making links to files; and 5025running `configure' scripts in subdirectories. Adding these features 5026enabled Ken to convert GNU `as', and Rob Savoye to convert DejaGNU, to 5027using Autoconf. 5028 5029 I added more features in response to other peoples' requests. Many 5030people had asked for `configure' scripts to share the results of the 5031checks between runs, because (particularly when configuring a large 5032source tree, like Cygnus does) they were frustratingly slow. Mike 5033Haertel suggested adding site-specific initialization scripts. People 5034distributing software that had to unpack on MS-DOS asked for a way to 5035override the `.in' extension on the file names, which produced file 5036names like `config.h.in' containing two dots. Jim Avera did an 5037extensive examination of the problems with quoting in `AC_DEFINE' and 5038`AC_SUBST'; his insights led to significant improvements. Richard 5039Stallman asked that compiler output be sent to `config.log' instead of 5040`/dev/null', to help people debug the Emacs `configure' script. 5041 5042 I made some other changes because of my dissatisfaction with the 5043quality of the program. I made the messages showing results of the 5044checks less ambiguous, always printing a result. I regularized the 5045names of the macros and cleaned up coding style inconsistencies. I 5046added some auxiliary utilities that I had developed to help convert 5047source code packages to use Autoconf. With the help of Franc,ois 5048Pinard, I made the macros not interrupt each others' messages. (That 5049feature revealed some performance bottlenecks in GNU `m4', which he 5050hastily corrected!) I reorganized the documentation around problems 5051people want to solve. And I began a testsuite, because experience had 5052shown that Autoconf has a pronounced tendency to regress when we change 5053it. 5054 5055 Again, several alpha testers gave invaluable feedback, especially 5056Franc,ois Pinard, Jim Meyering, Karl Berry, Rob Savoye, Ken Raeburn, 5057and Mark Eichin. 5058 5059 Finally, version 2.0 was ready. And there was much rejoicing. (And 5060I have free time again. I think. Yeah, right.) 5061 5062 5063File: autoconf.info, Node: Old Macro Names, Next: Environment Variable Index, Prev: History, Up: Top 5064 5065Old Macro Names 5066*************** 5067 5068 In version 2 of Autoconf, most of the macros were renamed to use a 5069more uniform and descriptive naming scheme. Here are the old names of 5070the macros that were renamed, followed by the current names of those 5071macros. Although the old names are still accepted by the `autoconf' 5072program for backward compatibility, the old names are considered 5073obsolete. *Note Macro Names::, for a description of the new naming 5074scheme. 5075 5076`AC_ALLOCA' 5077 `AC_FUNC_ALLOCA' 5078 5079`AC_ARG_ARRAY' 5080 removed because of limited usefulness 5081 5082`AC_CHAR_UNSIGNED' 5083 `AC_C_CHAR_UNSIGNED' 5084 5085`AC_CONST' 5086 `AC_C_CONST' 5087 5088`AC_CROSS_CHECK' 5089 `AC_C_CROSS' 5090 5091`AC_ERROR' 5092 `AC_MSG_ERROR' 5093 5094`AC_FIND_X' 5095 `AC_PATH_X' 5096 5097`AC_FIND_XTRA' 5098 `AC_PATH_XTRA' 5099 5100`AC_FUNC_CHECK' 5101 `AC_CHECK_FUNC' 5102 5103`AC_GCC_TRADITIONAL' 5104 `AC_PROG_GCC_TRADITIONAL' 5105 5106`AC_GETGROUPS_T' 5107 `AC_TYPE_GETGROUPS' 5108 5109`AC_GETLOADAVG' 5110 `AC_FUNC_GETLOADAVG' 5111 5112`AC_HAVE_FUNCS' 5113 `AC_CHECK_FUNCS' 5114 5115`AC_HAVE_HEADERS' 5116 `AC_CHECK_HEADERS' 5117 5118`AC_HAVE_POUNDBANG' 5119 `AC_SYS_INTERPRETER' (different calling convention) 5120 5121`AC_HEADER_CHECK' 5122 `AC_CHECK_HEADER' 5123 5124`AC_HEADER_EGREP' 5125 `AC_EGREP_HEADER' 5126 5127`AC_INLINE' 5128 `AC_C_INLINE' 5129 5130`AC_LN_S' 5131 `AC_PROG_LN_S' 5132 5133`AC_LONG_DOUBLE' 5134 `AC_C_LONG_DOUBLE' 5135 5136`AC_LONG_FILE_NAMES' 5137 `AC_SYS_LONG_FILE_NAMES' 5138 5139`AC_MAJOR_HEADER' 5140 `AC_HEADER_MAJOR' 5141 5142`AC_MINUS_C_MINUS_O' 5143 `AC_PROG_CC_C_O' 5144 5145`AC_MMAP' 5146 `AC_FUNC_MMAP' 5147 5148`AC_MODE_T' 5149 `AC_TYPE_MODE_T' 5150 5151`AC_OFF_T' 5152 `AC_TYPE_OFF_T' 5153 5154`AC_PID_T' 5155 `AC_TYPE_PID_T' 5156 5157`AC_PREFIX' 5158 `AC_PREFIX_PROGRAM' 5159 5160`AC_PROGRAMS_CHECK' 5161 `AC_CHECK_PROGS' 5162 5163`AC_PROGRAMS_PATH' 5164 `AC_PATH_PROGS' 5165 5166`AC_PROGRAM_CHECK' 5167 `AC_CHECK_PROG' 5168 5169`AC_PROGRAM_EGREP' 5170 `AC_EGREP_CPP' 5171 5172`AC_PROGRAM_PATH' 5173 `AC_PATH_PROG' 5174 5175`AC_REMOTE_TAPE' 5176 removed because of limited usefulness 5177 5178`AC_RESTARTABLE_SYSCALLS' 5179 `AC_SYS_RESTARTABLE_SYSCALLS' 5180 5181`AC_RETSIGTYPE' 5182 `AC_TYPE_SIGNAL' 5183 5184`AC_RSH' 5185 removed because of limited usefulness 5186 5187`AC_SETVBUF_REVERSED' 5188 `AC_FUNC_SETVBUF_REVERSED' 5189 5190`AC_SET_MAKE' 5191 `AC_PROG_MAKE_SET' 5192 5193`AC_SIZEOF_TYPE' 5194 `AC_CHECK_SIZEOF' 5195 5196`AC_SIZE_T' 5197 `AC_TYPE_SIZE_T' 5198 5199`AC_STAT_MACROS_BROKEN' 5200 `AC_HEADER_STAT' 5201 5202`AC_STDC_HEADERS' 5203 `AC_HEADER_STDC' 5204 5205`AC_STRCOLL' 5206 `AC_FUNC_STRCOLL' 5207 5208`AC_ST_BLKSIZE' 5209 `AC_STRUCT_ST_BLKSIZE' 5210 5211`AC_ST_BLOCKS' 5212 `AC_STRUCT_ST_BLOCKS' 5213 5214`AC_ST_RDEV' 5215 `AC_STRUCT_ST_RDEV' 5216 5217`AC_SYS_SIGLIST_DECLARED' 5218 `AC_DECL_SYS_SIGLIST' 5219 5220`AC_TEST_CPP' 5221 `AC_TRY_CPP' 5222 5223`AC_TEST_PROGRAM' 5224 `AC_TRY_RUN' 5225 5226`AC_TIMEZONE' 5227 `AC_STRUCT_TIMEZONE' 5228 5229`AC_TIME_WITH_SYS_TIME' 5230 `AC_HEADER_TIME' 5231 5232`AC_UID_T' 5233 `AC_TYPE_UID_T' 5234 5235`AC_UTIME_NULL' 5236 `AC_FUNC_UTIME_NULL' 5237 5238`AC_VFORK' 5239 `AC_FUNC_VFORK' 5240 5241`AC_VPRINTF' 5242 `AC_FUNC_VPRINTF' 5243 5244`AC_WAIT3' 5245 `AC_FUNC_WAIT3' 5246 5247`AC_WARN' 5248 `AC_MSG_WARN' 5249 5250`AC_WORDS_BIGENDIAN' 5251 `AC_C_BIGENDIAN' 5252 5253`AC_YYTEXT_POINTER' 5254 `AC_DECL_YYTEXT' 5255 5256 5257File: autoconf.info, Node: Environment Variable Index, Next: Output Variable Index, Prev: Old Macro Names, Up: Top 5258 5259Environment Variable Index 5260************************** 5261 5262 This is an alphabetical list of the environment variables that 5263Autoconf checks. 5264 5265* Menu: 5266 5267* AC_MACRODIR <1>: Invoking autoupdate. 5268* AC_MACRODIR <2>: Invoking autoheader. 5269* AC_MACRODIR <3>: Invoking autoreconf. 5270* AC_MACRODIR <4>: Invoking autoconf. 5271* AC_MACRODIR <5>: Invoking ifnames. 5272* AC_MACRODIR: Invoking autoscan. 5273* CONFIG_FILES: Invoking config.status. 5274* CONFIG_HEADERS: Invoking config.status. 5275* CONFIG_SHELL: Invoking config.status. 5276* CONFIG_SITE: Site Defaults. 5277* CONFIG_STATUS: Invoking config.status. 5278* SIMPLE_BACKUP_SUFFIX: Invoking autoupdate. 5279 5280 5281File: autoconf.info, Node: Output Variable Index, Next: Preprocessor Symbol Index, Prev: Environment Variable Index, Up: Top 5282 5283Output Variable Index 5284********************* 5285 5286 This is an alphabetical list of the variables that Autoconf can 5287substitute into files that it creates, typically one or more 5288`Makefile's. *Note Setting Output Variables::, for more information on 5289how this is done. 5290 5291* Menu: 5292 5293* ALLOCA: Particular Functions. 5294* AWK: Particular Programs. 5295* bindir: Preset Output Variables. 5296* build: System Type Variables. 5297* build_alias: System Type Variables. 5298* build_cpu: System Type Variables. 5299* build_os: System Type Variables. 5300* build_vendor: System Type Variables. 5301* CC <1>: UNIX Variants. 5302* CC: Particular Programs. 5303* CFLAGS <1>: Particular Programs. 5304* CFLAGS: Preset Output Variables. 5305* configure_input: Preset Output Variables. 5306* CPP: Particular Programs. 5307* CPPFLAGS: Preset Output Variables. 5308* CXX: Particular Programs. 5309* CXXCPP: Particular Programs. 5310* CXXFLAGS <1>: Particular Programs. 5311* CXXFLAGS: Preset Output Variables. 5312* datadir: Preset Output Variables. 5313* DEFS: Preset Output Variables. 5314* exec_prefix: Preset Output Variables. 5315* EXEEXT: System Services. 5316* F77: Particular Programs. 5317* FFLAGS <1>: Particular Programs. 5318* FFLAGS: Preset Output Variables. 5319* FLIBS: Fortran 77 Compiler Characteristics. 5320* host: System Type Variables. 5321* host_alias: System Type Variables. 5322* host_cpu: System Type Variables. 5323* host_os: System Type Variables. 5324* host_vendor: System Type Variables. 5325* includedir: Preset Output Variables. 5326* infodir: Preset Output Variables. 5327* INSTALL: Particular Programs. 5328* INSTALL_DATA: Particular Programs. 5329* INSTALL_PROGRAM: Particular Programs. 5330* INSTALL_SCRIPT: Particular Programs. 5331* KMEM_GROUP: Particular Functions. 5332* LDFLAGS: Preset Output Variables. 5333* LEX: Particular Programs. 5334* LEX_OUTPUT_ROOT: Particular Programs. 5335* LEXLIB: Particular Programs. 5336* libdir: Preset Output Variables. 5337* libexecdir: Preset Output Variables. 5338* LIBOBJS <1>: Structures. 5339* LIBOBJS <2>: Generic Functions. 5340* LIBOBJS: Particular Functions. 5341* LIBS <1>: UNIX Variants. 5342* LIBS: Preset Output Variables. 5343* LN_S: Particular Programs. 5344* localstatedir: Preset Output Variables. 5345* mandir: Preset Output Variables. 5346* NEED_SETGID: Particular Functions. 5347* OBJEXT: System Services. 5348* oldincludedir: Preset Output Variables. 5349* prefix: Preset Output Variables. 5350* program_transform_name: Transforming Names. 5351* RANLIB: Particular Programs. 5352* sbindir: Preset Output Variables. 5353* SET_MAKE: Output. 5354* sharedstatedir: Preset Output Variables. 5355* srcdir: Preset Output Variables. 5356* subdirs: Subdirectories. 5357* sysconfdir: Preset Output Variables. 5358* target: System Type Variables. 5359* target_alias: System Type Variables. 5360* target_cpu: System Type Variables. 5361* target_os: System Type Variables. 5362* target_vendor: System Type Variables. 5363* top_srcdir: Preset Output Variables. 5364* X_CFLAGS: System Services. 5365* X_EXTRA_LIBS: System Services. 5366* X_LIBS: System Services. 5367* X_PRE_LIBS: System Services. 5368* YACC: Particular Programs. 5369 5370 5371File: autoconf.info, Node: Preprocessor Symbol Index, Next: Macro Index, Prev: Output Variable Index, Up: Top 5372 5373Preprocessor Symbol Index 5374************************* 5375 5376 This is an alphabetical list of the C preprocessor symbols that the 5377Autoconf macros define. To work with Autoconf, C source code needs to 5378use these names in `#if' directives. 5379 5380* Menu: 5381 5382* __CHAR_UNSIGNED__: C Compiler Characteristics. 5383* _ALL_SOURCE: UNIX Variants. 5384* _MINIX: UNIX Variants. 5385* _POSIX_1_SOURCE: UNIX Variants. 5386* _POSIX_SOURCE: UNIX Variants. 5387* _POSIX_VERSION: Particular Headers. 5388* C_ALLOCA: Particular Functions. 5389* CLOSEDIR_VOID: Particular Functions. 5390* const: C Compiler Characteristics. 5391* DGUX: Particular Functions. 5392* DIRENT: Particular Headers. 5393* F77_NO_MINUS_C_MINUS_O: Particular Programs. 5394* GETGROUPS_T: Particular Typedefs. 5395* GETLODAVG_PRIVILEGED: Particular Functions. 5396* GETPGRP_VOID: Particular Functions. 5397* gid_t: Particular Typedefs. 5398* HAVE_ALLOCA_H: Particular Functions. 5399* HAVE_CONFIG_H: Configuration Headers. 5400* HAVE_DIRENT_H: Particular Headers. 5401* HAVE_DOPRNT: Particular Functions. 5402* HAVE_FUNCTION: Generic Functions. 5403* HAVE_GETMNTENT: Particular Functions. 5404* HAVE_HEADER: Generic Headers. 5405* HAVE_LONG_DOUBLE: C Compiler Characteristics. 5406* HAVE_LONG_FILE_NAMES: System Services. 5407* HAVE_MMAP: Particular Functions. 5408* HAVE_NDIR_H: Particular Headers. 5409* HAVE_RESTARTABLE_SYSCALLS: System Services. 5410* HAVE_ST_BLKSIZE: Structures. 5411* HAVE_ST_BLOCKS: Structures. 5412* HAVE_ST_RDEV: Structures. 5413* HAVE_STRCOLL: Particular Functions. 5414* HAVE_STRFTIME: Particular Functions. 5415* HAVE_STRINGIZE: C Compiler Characteristics. 5416* HAVE_SYS_DIR_H: Particular Headers. 5417* HAVE_SYS_NDIR_H: Particular Headers. 5418* HAVE_SYS_WAIT_H: Particular Headers. 5419* HAVE_TM_ZONE: Structures. 5420* HAVE_TZNAME: Structures. 5421* HAVE_UNISTD_H: Particular Headers. 5422* HAVE_UTIME_NULL: Particular Functions. 5423* HAVE_VFORK_H: Particular Functions. 5424* HAVE_VPRINTF: Particular Functions. 5425* HAVE_WAIT3: Particular Functions. 5426* inline: C Compiler Characteristics. 5427* INT_16_BITS: C Compiler Characteristics. 5428* LONG_64_BITS: C Compiler Characteristics. 5429* MAJOR_IN_MKDEV: Particular Headers. 5430* MAJOR_IN_SYSMACROS: Particular Headers. 5431* mode_t: Particular Typedefs. 5432* NDIR: Particular Headers. 5433* NEED_MEMORY_H: Particular Headers. 5434* NEED_SETGID: Particular Functions. 5435* NLIST_NAME_UNION: Particular Functions. 5436* NLIST_STRUCT: Particular Functions. 5437* NO_MINUS_C_MINUS_O: Particular Programs. 5438* off_t: Particular Typedefs. 5439* pid_t: Particular Typedefs. 5440* RETSIGTYPE: Particular Typedefs. 5441* SELECT_TYPE_ARG1: Particular Functions. 5442* SELECT_TYPE_ARG234: Particular Functions. 5443* SELECT_TYPE_ARG5: Particular Functions. 5444* SETPGRP_VOID: Particular Functions. 5445* SETVBUF_REVERSED: Particular Functions. 5446* size_t: Particular Typedefs. 5447* STDC_HEADERS: Particular Headers. 5448* SVR4: Particular Functions. 5449* SYS_SIGLIST_DECLARED: Particular Headers. 5450* SYSDIR: Particular Headers. 5451* SYSNDIR: Particular Headers. 5452* TIME_WITH_SYS_TIME: Structures. 5453* TM_IN_SYS_TIME: Structures. 5454* uid_t: Particular Typedefs. 5455* UMAX: Particular Functions. 5456* UMAX4_3: Particular Functions. 5457* USG: Particular Headers. 5458* vfork: Particular Functions. 5459* VOID_CLOSEDIR: Particular Headers. 5460* WORDS_BIGENDIAN: C Compiler Characteristics. 5461* YYTEXT_POINTER: Particular Programs. 5462 5463 5464File: autoconf.info, Node: Macro Index, Prev: Preprocessor Symbol Index, Up: Top 5465 5466Macro Index 5467*********** 5468 5469 This is an alphabetical list of the Autoconf macros. To make the 5470list easier to use, the macros are listed without their preceding `AC_'. 5471 5472* Menu: 5473 5474* AIX: UNIX Variants. 5475* ALLOCA: Old Macro Names. 5476* ARG_ARRAY: Old Macro Names. 5477* ARG_ENABLE: Package Options. 5478* ARG_PROGRAM: Transforming Names. 5479* ARG_WITH: External Software. 5480* BEFORE: Suggested Ordering. 5481* C_BIGENDIAN: C Compiler Characteristics. 5482* C_CHAR_UNSIGNED: C Compiler Characteristics. 5483* C_CONST: C Compiler Characteristics. 5484* C_CROSS: Test Programs. 5485* C_INLINE: C Compiler Characteristics. 5486* C_LONG_DOUBLE: C Compiler Characteristics. 5487* C_STRINGIZE: C Compiler Characteristics. 5488* CACHE_CHECK: Caching Results. 5489* CACHE_LOAD: Caching Results. 5490* CACHE_SAVE: Caching Results. 5491* CACHE_VAL: Caching Results. 5492* CANONICAL_HOST: Canonicalizing. 5493* CANONICAL_SYSTEM: Canonicalizing. 5494* CHAR_UNSIGNED: Old Macro Names. 5495* CHECK_FILE: Generic Programs. 5496* CHECK_FILES: Generic Programs. 5497* CHECK_FUNC: Generic Functions. 5498* CHECK_FUNCS: Generic Functions. 5499* CHECK_HEADER: Generic Headers. 5500* CHECK_HEADERS: Generic Headers. 5501* CHECK_LIB: Libraries. 5502* CHECK_PROG: Generic Programs. 5503* CHECK_PROGS: Generic Programs. 5504* CHECK_SIZEOF: C Compiler Characteristics. 5505* CHECK_TOOL: Generic Programs. 5506* CHECK_TYPE: Generic Typedefs. 5507* CHECKING: Printing Messages. 5508* COMPILE_CHECK: Examining Libraries. 5509* CONFIG_AUX_DIR: Input. 5510* CONFIG_HEADER: Configuration Headers. 5511* CONFIG_SUBDIRS: Subdirectories. 5512* CONST: Old Macro Names. 5513* CROSS_CHECK: Old Macro Names. 5514* CYGWIN: System Services. 5515* DECL_SYS_SIGLIST: Particular Headers. 5516* DECL_YYTEXT: Particular Programs. 5517* DEFINE: Defining Symbols. 5518* DEFINE_UNQUOTED: Defining Symbols. 5519* DEFUN: Macro Definitions. 5520* DIR_HEADER: Particular Headers. 5521* DYNIX_SEQ: UNIX Variants. 5522* EGREP_CPP: Examining Declarations. 5523* EGREP_HEADER: Examining Declarations. 5524* ENABLE: Package Options. 5525* ERROR: Old Macro Names. 5526* EXEEXT: System Services. 5527* F77_LIBRARY_LDFLAGS: Fortran 77 Compiler Characteristics. 5528* FIND_X: Old Macro Names. 5529* FIND_XTRA: Old Macro Names. 5530* FUNC_ALLOCA: Particular Functions. 5531* FUNC_CHECK: Old Macro Names. 5532* FUNC_CLOSEDIR_VOID: Particular Functions. 5533* FUNC_FNMATCH: Particular Functions. 5534* FUNC_GETLOADAVG: Particular Functions. 5535* FUNC_GETMNTENT: Particular Functions. 5536* FUNC_GETPGRP: Particular Functions. 5537* FUNC_MEMCMP: Particular Functions. 5538* FUNC_MMAP: Particular Functions. 5539* FUNC_SELECT_ARGTYPES: Particular Functions. 5540* FUNC_SETPGRP: Particular Functions. 5541* FUNC_SETVBUF_REVERSED: Particular Functions. 5542* FUNC_STRCOLL: Particular Functions. 5543* FUNC_STRFTIME: Particular Functions. 5544* FUNC_UTIME_NULL: Particular Functions. 5545* FUNC_VFORK: Particular Functions. 5546* FUNC_VPRINTF: Particular Functions. 5547* FUNC_WAIT3: Particular Functions. 5548* GCC_TRADITIONAL: Old Macro Names. 5549* GETGROUPS_T: Old Macro Names. 5550* GETLOADAVG: Old Macro Names. 5551* HAVE_FUNCS: Old Macro Names. 5552* HAVE_HEADERS: Old Macro Names. 5553* HAVE_LIBRARY: Libraries. 5554* HAVE_POUNDBANG: Old Macro Names. 5555* HEADER_CHECK: Old Macro Names. 5556* HEADER_DIRENT: Particular Headers. 5557* HEADER_EGREP: Old Macro Names. 5558* HEADER_MAJOR: Particular Headers. 5559* HEADER_STAT: Structures. 5560* HEADER_STDC: Particular Headers. 5561* HEADER_SYS_WAIT: Particular Headers. 5562* HEADER_TIME: Structures. 5563* INIT: Input. 5564* INLINE: Old Macro Names. 5565* INT_16_BITS: C Compiler Characteristics. 5566* IRIX_SUN: UNIX Variants. 5567* ISC_POSIX: UNIX Variants. 5568* LANG_C: Language Choice. 5569* LANG_CPLUSPLUS: Language Choice. 5570* LANG_FORTRAN77: Language Choice. 5571* LANG_RESTORE: Language Choice. 5572* LANG_SAVE: Language Choice. 5573* LINK_FILES: Using System Type. 5574* LN_S: Old Macro Names. 5575* LONG_64_BITS: C Compiler Characteristics. 5576* LONG_DOUBLE: Old Macro Names. 5577* LONG_FILE_NAMES: Old Macro Names. 5578* MAJOR_HEADER: Old Macro Names. 5579* MEMORY_H: Particular Headers. 5580* MINGW32: System Services. 5581* MINIX: UNIX Variants. 5582* MINUS_C_MINUS_O: Old Macro Names. 5583* MMAP: Old Macro Names. 5584* MODE_T: Old Macro Names. 5585* MSG_CHECKING: Printing Messages. 5586* MSG_ERROR: Printing Messages. 5587* MSG_RESULT: Printing Messages. 5588* MSG_WARN: Printing Messages. 5589* OBJEXT: System Services. 5590* OBSOLETE: Obsolete Macros. 5591* OFF_T: Old Macro Names. 5592* OUTPUT: Output. 5593* PATH_PROG: Generic Programs. 5594* PATH_PROGS: Generic Programs. 5595* PATH_X: System Services. 5596* PATH_XTRA: System Services. 5597* PID_T: Old Macro Names. 5598* PREFIX: Old Macro Names. 5599* PREFIX_PROGRAM: Default Prefix. 5600* PREREQ: Versions. 5601* PROG_AWK: Particular Programs. 5602* PROG_CC: Particular Programs. 5603* PROG_CC_C_O: Particular Programs. 5604* PROG_CPP: Particular Programs. 5605* PROG_CXX: Particular Programs. 5606* PROG_CXXCPP: Particular Programs. 5607* PROG_F77_C_O: Particular Programs. 5608* PROG_FORTRAN: Particular Programs. 5609* PROG_GCC_TRADITIONAL: Particular Programs. 5610* PROG_INSTALL: Particular Programs. 5611* PROG_LEX: Particular Programs. 5612* PROG_LN_S: Particular Programs. 5613* PROG_MAKE_SET: Output. 5614* PROG_RANLIB: Particular Programs. 5615* PROG_YACC: Particular Programs. 5616* PROGRAM_CHECK: Old Macro Names. 5617* PROGRAM_EGREP: Old Macro Names. 5618* PROGRAM_PATH: Old Macro Names. 5619* PROGRAMS_CHECK: Old Macro Names. 5620* PROGRAMS_PATH: Old Macro Names. 5621* PROVIDE: Prerequisite Macros. 5622* REMOTE_TAPE: Old Macro Names. 5623* REPLACE_FUNCS: Generic Functions. 5624* REQUIRE: Prerequisite Macros. 5625* REQUIRE_CPP: Language Choice. 5626* RESTARTABLE_SYSCALLS: Old Macro Names. 5627* RETSIGTYPE: Old Macro Names. 5628* REVISION: Versions. 5629* RSH: Old Macro Names. 5630* SCO_INTL: UNIX Variants. 5631* SEARCH_LIBS: Libraries. 5632* SET_MAKE: Old Macro Names. 5633* SETVBUF_REVERSED: Old Macro Names. 5634* SIZE_T: Old Macro Names. 5635* SIZEOF_TYPE: Old Macro Names. 5636* ST_BLKSIZE: Old Macro Names. 5637* ST_BLOCKS: Old Macro Names. 5638* ST_RDEV: Old Macro Names. 5639* STAT_MACROS_BROKEN <1>: Old Macro Names. 5640* STAT_MACROS_BROKEN: Structures. 5641* STDC_HEADERS: Old Macro Names. 5642* STRCOLL: Old Macro Names. 5643* STRUCT_ST_BLKSIZE: Structures. 5644* STRUCT_ST_BLOCKS: Structures. 5645* STRUCT_ST_RDEV: Structures. 5646* STRUCT_TIMEZONE: Structures. 5647* STRUCT_TM: Structures. 5648* SUBST: Setting Output Variables. 5649* SUBST_FILE: Setting Output Variables. 5650* SYS_INTERPRETER: System Services. 5651* SYS_LONG_FILE_NAMES: System Services. 5652* SYS_RESTARTABLE_SYSCALLS: System Services. 5653* SYS_SIGLIST_DECLARED: Old Macro Names. 5654* TEST_CPP: Old Macro Names. 5655* TEST_PROGRAM: Old Macro Names. 5656* TIME_WITH_SYS_TIME: Old Macro Names. 5657* TIMEZONE: Old Macro Names. 5658* TRY_COMPILE: Examining Syntax. 5659* TRY_CPP: Examining Declarations. 5660* TRY_LINK: Examining Libraries. 5661* TRY_LINK_FUNC: Examining Libraries. 5662* TRY_RUN: Test Programs. 5663* TYPE_GETGROUPS: Particular Typedefs. 5664* TYPE_MODE_T: Particular Typedefs. 5665* TYPE_OFF_T: Particular Typedefs. 5666* TYPE_PID_T: Particular Typedefs. 5667* TYPE_SIGNAL: Particular Typedefs. 5668* TYPE_SIZE_T: Particular Typedefs. 5669* TYPE_UID_T: Particular Typedefs. 5670* UID_T: Old Macro Names. 5671* UNISTD_H: Particular Headers. 5672* USG: Particular Headers. 5673* UTIME_NULL: Old Macro Names. 5674* VALIDATE_CACHED_SYSTEM_TUPLE: Canonicalizing. 5675* VERBOSE: Printing Messages. 5676* VFORK: Old Macro Names. 5677* VPRINTF: Old Macro Names. 5678* WAIT3: Old Macro Names. 5679* WARN: Old Macro Names. 5680* WITH: External Software. 5681* WORDS_BIGENDIAN: Old Macro Names. 5682* XENIX_DIR: UNIX Variants. 5683* YYTEXT_POINTER: Old Macro Names. 5684 5685 5686 5687Tag Table: 5688Node: Top1209 5689Node: Introduction9711 5690Node: Making configure Scripts13551 5691Node: Writing configure.in16632 5692Node: Invoking autoscan20365 5693Node: Invoking ifnames22670 5694Node: Invoking autoconf24160 5695Node: Invoking autoreconf25998 5696Node: Setup28834 5697Node: Input29739 5698Node: Output31476 5699Node: Makefile Substitutions35113 5700Node: Preset Output Variables36716 5701Node: Build Directories41585 5702Node: Automatic Remaking43218 5703Node: Configuration Headers45304 5704Node: Header Templates47818 5705Node: Invoking autoheader49027 5706Node: Subdirectories52175 5707Node: Default Prefix53570 5708Node: Versions54974 5709Node: Existing Tests56878 5710Node: Alternative Programs58426 5711Node: Particular Programs59113 5712Node: Generic Programs67165 5713Node: Libraries70471 5714Node: Library Functions73545 5715Node: Particular Functions74103 5716Node: Generic Functions81297 5717Node: Header Files83401 5718Node: Particular Headers83960 5719Node: Generic Headers90952 5720Node: Structures92254 5721Node: Typedefs94491 5722Node: Particular Typedefs94997 5723Node: Generic Typedefs96214 5724Node: C Compiler Characteristics96671 5725Node: Fortran 77 Compiler Characteristics99542 5726Node: System Services101245 5727Node: UNIX Variants104381 5728Node: Writing Tests106400 5729Node: Examining Declarations108393 5730Node: Examining Syntax110885 5731Node: Examining Libraries112330 5732Node: Run Time116040 5733Node: Test Programs117028 5734Node: Guidelines119356 5735Node: Test Functions120545 5736Node: Portable Shell122088 5737Node: Testing Values and Files124020 5738Node: Multiple Cases125675 5739Node: Language Choice126873 5740Node: Results128975 5741Node: Defining Symbols129737 5742Node: Setting Output Variables133033 5743Node: Caching Results134879 5744Node: Cache Variable Names137625 5745Node: Cache Files139109 5746Node: Printing Messages141946 5747Node: Writing Macros145394 5748Node: Macro Definitions146041 5749Node: Macro Names147169 5750Node: Quoting149620 5751Node: Dependencies Between Macros151522 5752Node: Prerequisite Macros152169 5753Node: Suggested Ordering153660 5754Node: Obsolete Macros155190 5755Node: Manual Configuration156414 5756Node: Specifying Names157313 5757Node: Canonicalizing159214 5758Node: System Type Variables160726 5759Node: Using System Type161473 5760Node: Site Configuration162967 5761Node: External Software163740 5762Node: Package Options166943 5763Node: Site Details169690 5764Node: Transforming Names170913 5765Node: Transformation Options172091 5766Node: Transformation Examples172584 5767Node: Transformation Rules174152 5768Node: Site Defaults175561 5769Node: Invoking configure179467 5770Node: Basic Installation180416 5771Node: Compilers and Options182996 5772Node: Multiple Architectures183645 5773Node: Installation Names184631 5774Node: Optional Features185815 5775Node: System Type186585 5776Node: Sharing Defaults187607 5777Node: Operation Controls188231 5778Node: Invoking config.status189217 5779Node: Questions192605 5780Node: Distributing193137 5781Node: Why GNU m4194281 5782Node: Bootstrapping195094 5783Node: Why Not Imake195710 5784Node: Upgrading200119 5785Node: Changed File Names201640 5786Node: Changed Makefiles202394 5787Node: Changed Macros203490 5788Node: Invoking autoupdate204737 5789Node: Changed Results206328 5790Node: Changed Macro Writing208430 5791Node: History209693 5792Node: Genesis210485 5793Node: Exodus211674 5794Node: Leviticus214723 5795Node: Numbers216246 5796Node: Deuteronomy218162 5797Node: Old Macro Names220826 5798Node: Environment Variable Index223875 5799Node: Output Variable Index224889 5800Node: Preprocessor Symbol Index230087 5801Node: Macro Index235373 5802 5803End Tag Table 5804