1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
# frexp.m4 serial 7
dnl Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_FREXP],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
FREXP_LIBM=
AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
[gl_cv_func_frexp_no_libm],
[
AC_TRY_LINK([#include <math.h>
double x;],
[int e; return frexp (x, &e) > 0;],
[gl_cv_func_frexp_no_libm=yes],
[gl_cv_func_frexp_no_libm=no])
])
if test $gl_cv_func_frexp_no_libm = no; then
AC_CACHE_CHECK([whether frexp() can be used with libm],
[gl_cv_func_frexp_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_TRY_LINK([#include <math.h>
double x;],
[int e; return frexp (x, &e) > 0;],
[gl_cv_func_frexp_in_libm=yes],
[gl_cv_func_frexp_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_frexp_in_libm = yes; then
FREXP_LIBM=-lm
fi
fi
if test $gl_cv_func_frexp_no_libm = yes \
|| test $gl_cv_func_frexp_in_libm = yes; then
save_LIBS="$LIBS"
LIBS="$LIBS $FREXP_LIBM"
gl_FUNC_FREXP_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_frexp_works" in
*yes) gl_func_frexp=yes ;;
*) gl_func_frexp=no; REPLACE_FREXP=1; FREXP_LIBM= ;;
esac
else
gl_func_frexp=no
fi
if test $gl_func_frexp = yes; then
AC_DEFINE([HAVE_FREXP], [1],
[Define if the frexp() function is available and works.])
else
AC_LIBOBJ([frexp])
fi
AC_SUBST([FREXP_LIBM])
])
AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
[gl_cv_func_frexp_no_libm],
[
AC_TRY_LINK([#include <math.h>
double x;],
[int e; return frexp (x, &e) > 0;],
[gl_cv_func_frexp_no_libm=yes],
[gl_cv_func_frexp_no_libm=no])
])
if test $gl_cv_func_frexp_no_libm = yes; then
gl_FUNC_FREXP_WORKS
case "$gl_cv_func_frexp_works" in
*yes) gl_func_frexp_no_libm=yes ;;
*) gl_func_frexp_no_libm=no; REPLACE_FREXP=1 ;;
esac
else
gl_func_frexp_no_libm=no
dnl Set REPLACE_FREXP here because the system may have frexp in libm.
REPLACE_FREXP=1
fi
if test $gl_func_frexp_no_libm = yes; then
AC_DEFINE([HAVE_FREXP_IN_LIBC], [1],
[Define if the frexp() function is available in libc.])
else
AC_LIBOBJ([frexp])
fi
])
dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on
dnl NetBSD 3.0), on infinite numbers (this fails e.g. on IRIX 6.5 and mingw),
dnl and on negative zero (this fails e.g. on NetBSD 4.99).
AC_DEFUN([gl_FUNC_FREXP_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether frexp works], [gl_cv_func_frexp_works],
[
AC_TRY_RUN([
#include <float.h>
#include <math.h>
#include <string.h>
int main()
{
int i;
volatile double x;
/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
So we use -zero instead. */
double zero = 0.0;
/* Test on denormalized numbers. */
for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
;
if (x > 0.0)
{
int exp;
double y = frexp (x, &exp);
/* On machines with IEEE754 arithmetic: x = 1.11254e-308, exp = -1022.
On NetBSD: y = 0.75. Correct: y = 0.5. */
if (y != 0.5)
return 1;
}
/* Test on infinite numbers. */
x = 1.0 / 0.0;
{
int exp;
double y = frexp (x, &exp);
if (y != x)
return 1;
}
/* Test on negative zero. */
x = -zero;
{
int exp;
double y = frexp (x, &exp);
if (memcmp (&y, &x, sizeof x))
return 1;
}
return 0;
}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
[case "$host_os" in
netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
*) gl_cv_func_frexp_works="guessing yes";;
esac
])
])
])
|
