1/* error-checking interface to strtod-like functions 2 3 Copyright (C) 1996, 1999, 2000, 2003, 2004 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 18 19/* Written by Jim Meyering. */ 20 21#ifdef HAVE_CONFIG_H 22# include <config.h> 23#endif 24 25#include "xstrtod.h" 26 27#include <errno.h> 28#include <limits.h> 29#include <stdio.h> 30 31/* Tell the compiler that non-default rounding modes are used. */ 32#if 199901 <= __STDC_VERSION__ 33 #pragma STDC FENV_ACCESS ON 34#endif 35 36/* An interface to strtod that encapsulates all the error checking 37 one should usually perform. Like strtod, but upon successful 38 conversion put the result in *RESULT and return true. Return 39 false and don't modify *RESULT upon any failure. CONVERT 40 specifies the conversion function, e.g., strtod itself. */ 41 42bool 43xstrtod (char const *str, char const **ptr, double *result, 44 double (*convert) (char const *, char **)) 45{ 46 double val; 47 char *terminator; 48 bool ok = true; 49 50 errno = 0; 51 val = convert (str, &terminator); 52 53 /* Having a non-zero terminator is an error only when PTR is NULL. */ 54 if (terminator == str || (ptr == NULL && *terminator != '\0')) 55 ok = false; 56 else 57 { 58 /* Allow underflow (in which case strtod returns zero), 59 but flag overflow as an error. */ 60 if (val != 0.0 && errno == ERANGE) 61 ok = false; 62 } 63 64 if (ptr != NULL) 65 *ptr = terminator; 66 67 *result = val; 68 return ok; 69} 70