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# ldexp.m4 serial 1
dnl Copyright (C) 2010-2020 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_LDEXP],
[
AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM])
LDEXP_LIBM=
if test $gl_cv_func_ldexp_no_libm = no; then
AC_CACHE_CHECK([whether ldexp() can be used with libm],
[gl_cv_func_ldexp_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
double (*funcptr) (double, int) = ldexp;
double x;]],
[[return ldexp (x, -1) > 0;]])],
[gl_cv_func_ldexp_in_libm=yes],
[gl_cv_func_ldexp_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_ldexp_in_libm = yes; then
LDEXP_LIBM=-lm
fi
fi
AC_SUBST([LDEXP_LIBM])
])
dnl Test whether ldexp() can be used without linking with libm.
dnl Set gl_cv_func_ldexp_no_libm to 'yes' or 'no' accordingly.
AC_DEFUN([gl_CHECK_LDEXP_NO_LIBM],
[
AC_CACHE_CHECK([whether ldexp() can be used without linking with libm],
[gl_cv_func_ldexp_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
double (*funcptr) (double, int) = ldexp;
double x;]],
[[return ldexp (x, -1) > 0;]])],
[gl_cv_func_ldexp_no_libm=yes],
[gl_cv_func_ldexp_no_libm=no])
])
])
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