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# frexpl.m4
# serial 24
dnl Copyright (C) 2007-2024 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_FREXPL],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
dnl Persuade glibc <math.h> to declare frexpl().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Check whether it's declared.
dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
FREXPL_LIBM=
if test $HAVE_DECL_FREXPL = 1; then
gl_CHECK_FREXPL_NO_LIBM
if test $gl_cv_func_frexpl_no_libm = no; then
AC_CACHE_CHECK([whether frexpl() can be used with libm],
[gl_cv_func_frexpl_in_libm],
[
saved_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
long double x;]],
[[int e; return frexpl (x, &e) > 0;]])],
[gl_cv_func_frexpl_in_libm=yes],
[gl_cv_func_frexpl_in_libm=no])
LIBS="$saved_LIBS"
])
if test $gl_cv_func_frexpl_in_libm = yes; then
FREXPL_LIBM=-lm
fi
fi
if test $gl_cv_func_frexpl_no_libm = yes \
|| test $gl_cv_func_frexpl_in_libm = yes; then
saved_LIBS="$LIBS"
LIBS="$LIBS $FREXPL_LIBM"
gl_FUNC_FREXPL_WORKS
LIBS="$saved_LIBS"
case "$gl_cv_func_frexpl_works" in
*yes) gl_func_frexpl=yes ;;
*) gl_func_frexpl=no; REPLACE_FREXPL=1 ;;
esac
else
gl_func_frexpl=no
fi
if test $gl_func_frexpl = yes; then
AC_DEFINE([HAVE_FREXPL], [1],
[Define if the frexpl() function is available.])
fi
fi
if test $HAVE_DECL_FREXPL = 0 || test $gl_func_frexpl = no; then
dnl Find libraries needed to link lib/frexpl.c.
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
AC_REQUIRE([gl_FUNC_FREXP])
FREXPL_LIBM="$FREXP_LIBM"
else
FREXPL_LIBM=
fi
fi
AC_SUBST([FREXPL_LIBM])
])
AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
dnl Check whether it's declared.
dnl Mac OS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [[#include <math.h>]])
if test $HAVE_DECL_FREXPL = 1; then
gl_CHECK_FREXPL_NO_LIBM
if test $gl_cv_func_frexpl_no_libm = yes; then
gl_FUNC_FREXPL_WORKS
case "$gl_cv_func_frexpl_works" in
*yes) gl_func_frexpl_no_libm=yes ;;
*) gl_func_frexpl_no_libm=no; REPLACE_FREXPL=1 ;;
esac
else
gl_func_frexpl_no_libm=no
dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
REPLACE_FREXPL=1
fi
if test $gl_func_frexpl_no_libm = yes; then
AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
[Define if the frexpl() function is available in libc.])
fi
fi
])
dnl Test whether frexpl() can be used without linking with libm.
dnl Set gl_cv_func_frexpl_no_libm to 'yes' or 'no' accordingly.
AC_DEFUN([gl_CHECK_FREXPL_NO_LIBM],
[
AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
[gl_cv_func_frexpl_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
long double x;]],
[[int e; return frexpl (x, &e) > 0;]])],
[gl_cv_func_frexpl_no_libm=yes],
[gl_cv_func_frexpl_no_libm=no])
])
])
dnl Test whether frexpl() works on finite numbers (this fails on
dnl Mac OS X 10.4/PowerPC, on AIX 5.1, and on BeOS), on denormalized numbers
dnl (this fails on Mac OS X 10.5/i386), and also on infinite numbers (this
dnl fails e.g. on IRIX 6.5 and mingw).
AC_DEFUN([gl_FUNC_FREXPL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <float.h>
#include <math.h>
/* Override the values of <float.h>, like done in float.in.h. */
#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP (-16381)
#endif
#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP (-16381)
#endif
#if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP DBL_MIN_EXP
#endif
#if defined __sgi && (LDBL_MANT_DIG >= 106)
# if defined __GNUC__
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP DBL_MIN_EXP
# endif
#endif
extern
#ifdef __cplusplus
"C"
#endif
long double frexpl (long double, int *);
long double zero = 0.0L;
int main()
{
int result = 0;
volatile long double x;
/* Test on finite numbers that fails on AIX 5.1. */
x = 16.0L;
{
int exp = -9999;
frexpl (x, &exp);
if (exp != 5)
result |= 1;
}
/* Test on finite numbers that fails on Mac OS X 10.4, because its frexpl
function returns an invalid (incorrectly normalized) value: it returns
y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
but the correct result is
0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 } */
x = 1.01L;
{
int exp = -9999;
long double y = frexpl (x, &exp);
if (!(exp == 1 && y == 0.505L))
result |= 2;
}
/* Test on large finite numbers. This fails on BeOS at i = 16322, while
LDBL_MAX_EXP = 16384.
In the loop end test, we test x against Infinity, rather than comparing
i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP. */
{
int i;
for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
{
int exp = -9999;
frexpl (x, &exp);
if (exp != i)
{
result |= 4;
break;
}
}
}
/* Test on denormalized numbers. */
{
int i;
for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
;
if (x > 0.0L)
{
int exp;
long double y = frexpl (x, &exp);
/* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
exp = -16382, y = 0.5. On Mac OS X 10.5: exp = -16384, y = 0.5. */
if (exp != LDBL_MIN_EXP - 1)
result |= 8;
}
}
/* Test on infinite numbers. */
/* The Microsoft MSVC 14 compiler chokes on the expression 1.0 / 0.0. */
x = 1.0L / zero;
{
int exp;
long double y = frexpl (x, &exp);
if (y != x)
result |= 16;
}
return result;
}]])],
[gl_cv_func_frexpl_works=yes],
[gl_cv_func_frexpl_works=no],
[
changequote(,)dnl
case "$host_os" in
aix | aix[3-6]* | beos* | darwin* | irix* | mingw* | windows* | pw*)
gl_cv_func_frexpl_works="guessing no";;
*) gl_cv_func_frexpl_works="guessing yes";;
esac
changequote([,])dnl
])
])
])
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