2 dnl Copyright (C) 2002-2003, 2006-2011 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_STRTOD],
9 AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
10 dnl Test whether strtod is declared.
11 dnl Don't call AC_FUNC_STRTOD, because it does not have the right guess
12 dnl when cross-compiling.
13 dnl Don't call AC_CHECK_FUNCS([strtod]) because it would collide with the
14 dnl ac_cv_func_strtod variable set by the AC_FUNC_STRTOD macro.
15 AC_CHECK_DECLS_ONCE([strtod])
16 if test $ac_cv_have_decl_strtod != yes; then
19 AC_CACHE_CHECK([whether strtod obeys C99], [gl_cv_func_strtod_works],
20 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
24 /* Compare two numbers with ==.
25 This is a separate function because IRIX 6.5 "cc -O" miscompiles an
28 numeric_equal (double x, double y)
35 /* In some old versions of Linux (2000 or before), strtod mis-parses
36 strings with leading '+'. */
37 const char *string = " +69";
39 double value = strtod (string, &term);
40 if (value != 69 || term != (string + 4))
44 /* Under Solaris 2.4, strtod returns the wrong value for the
45 terminating character under some conditions. */
46 const char *string = "NaN";
48 strtod (string, &term);
49 if (term != string && *(term - 1) == 0)
53 /* Older glibc and Cygwin mis-parse "-0x". */
54 const char *string = "-0x";
56 double value = strtod (string, &term);
58 if (1.0 / value != -1.0 / zero || term != (string + 2))
62 /* Many platforms do not parse hex floats. */
63 const char *string = "0XaP+1";
65 double value = strtod (string, &term);
66 if (value != 20.0 || term != (string + 6))
70 /* Many platforms do not parse infinities. HP-UX 11.31 parses inf,
71 but mistakenly sets errno. */
72 const char *string = "inf";
76 value = strtod (string, &term);
77 if (value != HUGE_VAL || term != (string + 3) || errno)
81 /* glibc 2.7 and cygwin 1.5.24 misparse "nan()". */
82 const char *string = "nan()";
84 double value = strtod (string, &term);
85 if (numeric_equal (value, value) || term != (string + 5))
89 /* darwin 10.6.1 misparses "nan(". */
90 const char *string = "nan(";
92 double value = strtod (string, &term);
93 if (numeric_equal (value, value) || term != (string + 3))
98 [gl_cv_func_strtod_works=yes],
99 [gl_cv_func_strtod_works=no],
100 [dnl The last known bugs in glibc strtod(), as of this writing,
101 dnl were fixed in version 2.8
102 AC_EGREP_CPP([Lucky user],
104 #include <features.h>
105 #ifdef __GNU_LIBRARY__
106 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 8) || (__GLIBC__ > 2)) \
107 && !defined __UCLIBC__
112 [gl_cv_func_strtod_works=yes],
113 [gl_cv_func_strtod_works="guessing no"])])])
114 if test "$gl_cv_func_strtod_works" != yes; then
118 if test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1; then
124 # Prerequisites of lib/strtod.c.
125 AC_DEFUN([gl_PREREQ_STRTOD], [
126 AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM])
127 if test $gl_cv_func_ldexp_no_libm = yes; then
128 AC_DEFINE([HAVE_LDEXP_IN_LIBC], [1],
129 [Define if the ldexp function is available in libc.])