1/* Emulation of getpagesize() for systems that need it. */
2
3/*
4
5NAME
6
7	getpagesize -- return the number of bytes in page of memory
8
9SYNOPSIS
10
11	int getpagesize (void)
12
13DESCRIPTION
14
15	Returns the number of bytes in a page of memory.  This is the
16	granularity of many of the system memory management routines.
17	No guarantee is made as to whether or not it is the same as the
18	basic memory management hardware page size.
19
20BUGS
21
22	Is intended as a reasonable replacement for systems where this
23	is not provided as a system call.  The value of 4096 may or may
24	not be correct for the systems where it is returned as the default
25	value.
26
27*/
28
29#ifndef VMS
30
31#include "config.h"
32
33#include <sys/types.h>
34#ifdef HAVE_SYS_PARAM_H
35#include <sys/param.h>
36#endif
37
38#undef GNU_OUR_PAGESIZE
39#if defined (HAVE_SYSCONF) && defined (HAVE_UNISTD_H)
40#include <unistd.h>
41#ifdef _SC_PAGESIZE
42#define GNU_OUR_PAGESIZE sysconf(_SC_PAGESIZE)
43#endif
44#endif
45
46#ifndef GNU_OUR_PAGESIZE
47# ifdef	PAGESIZE
48#  define	GNU_OUR_PAGESIZE PAGESIZE
49# else	/* no PAGESIZE */
50#  ifdef	EXEC_PAGESIZE
51#   define	GNU_OUR_PAGESIZE EXEC_PAGESIZE
52#  else	/* no EXEC_PAGESIZE */
53#   ifdef	NBPG
54#    define	GNU_OUR_PAGESIZE (NBPG * CLSIZE)
55#    ifndef	CLSIZE
56#     define	CLSIZE 1
57#    endif	/* CLSIZE */
58#   else	/* no NBPG */
59#    ifdef	NBPC
60#     define	GNU_OUR_PAGESIZE NBPC
61#    else	/* no NBPC */
62#     define	GNU_OUR_PAGESIZE 4096	/* Just punt and use reasonable value */
63#    endif /* NBPC */
64#   endif /* NBPG */
65#  endif /* EXEC_PAGESIZE */
66# endif /* PAGESIZE */
67#endif /* GNU_OUR_PAGESIZE */
68
69int
70getpagesize ()
71{
72  return (GNU_OUR_PAGESIZE);
73}
74
75#else /* VMS */
76
77#if 0	/* older distributions of gcc-vms are missing <syidef.h> */
78#include <syidef.h>
79#endif
80#ifndef SYI$_PAGE_SIZE	/* VMS V5.4 and earlier didn't have this yet */
81#define SYI$_PAGE_SIZE 4452
82#endif
83extern unsigned long lib$getsyi(const unsigned short *,...);
84
85int getpagesize ()
86{
87  long pagsiz = 0L;
88  unsigned short itmcod = SYI$_PAGE_SIZE;
89
90  (void) lib$getsyi (&itmcod, (void *) &pagsiz);
91  if (pagsiz == 0L)
92    pagsiz = 512L;	/* VAX default */
93  return (int) pagsiz;
94}
95
96#endif /* VMS */
97