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# ldexpl.m4 serial 18
dnl Copyright (C) 2007-2023 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_LDEXPL],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
AC_REQUIRE([gl_FUNC_ISNANL]) dnl for ISNANL_LIBM
dnl Persuade glibc <math.h> to declare ldexpl().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Check whether it's declared.
dnl Mac OS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [[#include <math.h>]])
LDEXPL_LIBM=
if test $HAVE_DECL_LDEXPL = 1; then
gl_CHECK_LDEXPL_NO_LIBM
if test $gl_cv_func_ldexpl_no_libm = no; then
AC_CACHE_CHECK([whether ldexpl() can be used with libm],
[gl_cv_func_ldexpl_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
long double x;]],
[[return ldexpl (x, -1) > 0;]])],
[gl_cv_func_ldexpl_in_libm=yes],
[gl_cv_func_ldexpl_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_ldexpl_in_libm = yes; then
LDEXPL_LIBM=-lm
fi
fi
if test $gl_cv_func_ldexpl_no_libm = yes \
|| test $gl_cv_func_ldexpl_in_libm = yes; then
save_LIBS="$LIBS"
LIBS="$LIBS $LDEXPL_LIBM"
gl_FUNC_LDEXPL_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_ldexpl_works" in
*yes) gl_func_ldexpl=yes ;;
*) gl_func_ldexpl=no; REPLACE_LDEXPL=1 ;;
esac
else
gl_func_ldexpl=no
fi
if test $gl_func_ldexpl = yes; then
AC_DEFINE([HAVE_LDEXPL], [1],
[Define if the ldexpl() function is available.])
fi
fi
if test $HAVE_DECL_LDEXPL = 0 || test $gl_func_ldexpl = no; then
dnl Find libraries needed to link lib/ldexpl.c.
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
AC_REQUIRE([gl_FUNC_LDEXP])
LDEXPL_LIBM="$LDEXP_LIBM"
else
LDEXPL_LIBM="$ISNANL_LIBM"
fi
fi
AC_SUBST([LDEXPL_LIBM])
])
dnl Test whether ldexpl() can be used without linking with libm.
dnl Set gl_cv_func_ldexpl_no_libm to 'yes' or 'no' accordingly.
AC_DEFUN([gl_CHECK_LDEXPL_NO_LIBM],
[
AC_CACHE_CHECK([whether ldexpl() can be used without linking with libm],
[gl_cv_func_ldexpl_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
long double x;]],
[[return ldexpl (x, -1) > 0;]])],
[gl_cv_func_ldexpl_no_libm=yes],
[gl_cv_func_ldexpl_no_libm=no])
])
])
dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1
dnl and Mac OS X 10.4/PowerPC).
AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether ldexpl works], [gl_cv_func_ldexpl_works],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <math.h>
extern
#ifdef __cplusplus
"C"
#endif
long double ldexpl (long double, int);
int main()
{
int result = 0;
{
volatile long double x = 1.0;
volatile long double y = ldexpl (x, -1);
if (y != 0.5L)
result |= 1;
}
{
volatile long double x = 1.73205L;
volatile long double y = ldexpl (x, 0);
if (y != x)
result |= 2;
}
return result;
}]])],
[gl_cv_func_ldexpl_works=yes],
[gl_cv_func_ldexpl_works=no],
[
changequote(,)dnl
case "$host_os" in
aix | aix[3-6]*) gl_cv_func_ldexpl_works="guessing no" ;;
# Guess yes on native Windows.
mingw* | windows*) gl_cv_func_ldexpl_works="guessing yes" ;;
*) gl_cv_func_ldexpl_works="guessing yes" ;;
esac
changequote([,])dnl
])
])
])
|
