1 /* Convert string to double, using the C locale.
3 Copyright (C) 2003, 2004, 2006, 2009 Free Software Foundation, Inc.
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 3 of the License, or
8 (at your option) any later version.
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.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 /* Written by Paul Eggert. */
20 #include <config.h>
22 #include "c-strtod.h"
24 #include <errno.h>
25 #include <locale.h>
26 #include <stdlib.h>
27 #include <string.h>
29 #if LONG
30 # define C_STRTOD c_strtold
31 # define DOUBLE long double
32 # define STRTOD_L strtold_l
33 #else
34 # define C_STRTOD c_strtod
35 # define DOUBLE double
36 # define STRTOD_L strtod_l
37 #endif
39 /* c_strtold falls back on strtod if strtold doesn't conform to C99. */
40 #if LONG && HAVE_C99_STRTOLD
41 # define STRTOD strtold
42 #else
43 # define STRTOD strtod
44 #endif
46 #ifdef LC_ALL_MASK
48 /* Cache for the C locale object.
49 Marked volatile so that different threads see the same value
50 (avoids locking). */
51 static volatile locale_t c_locale_cache;
53 /* Return the C locale object, or (locale_t) 0 with errno set
54 if it cannot be created. */
55 static inline locale_t
56 c_locale (void)
57 {
58 if (!c_locale_cache)
59 c_locale_cache = newlocale (LC_ALL_MASK, "C", (locale_t) 0);
60 return c_locale_cache;
61 }
63 #endif
65 DOUBLE
66 C_STRTOD (char const *nptr, char **endptr)
67 {
68 DOUBLE r;
70 #ifdef LC_ALL_MASK
72 locale_t locale = c_locale ();
73 if (!locale)
74 {
75 if (endptr)
76 *endptr = (char *) nptr;
77 return 0; /* errno is set here */
78 }
80 r = STRTOD_L (nptr, endptr, locale);
82 #else
84 char *saved_locale = setlocale (LC_NUMERIC, NULL);
86 if (saved_locale)
87 {
88 saved_locale = strdup (saved_locale);
89 if (saved_locale == NULL)
90 {
91 if (endptr)
92 *endptr = (char *) nptr;
93 return 0; /* errno is set here */
94 }
95 setlocale (LC_NUMERIC, "C");
96 }
98 r = STRTOD (nptr, endptr);
100 if (saved_locale)
101 {
102 int saved_errno = errno;
104 setlocale (LC_NUMERIC, saved_locale);
105 free (saved_locale);
106 errno = saved_errno;
107 }
109 #endif
111 return r;
112 }