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# truncl.m4
# serial 21
dnl Copyright (C) 2007-2008, 2010-2026 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.
dnl This file is offered as-is, without any warranty.
AC_DEFUN([gl_FUNC_TRUNCL],
[
m4_divert_text([DEFAULTS], [gl_truncl_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
dnl Persuade glibc <math.h> to declare truncl().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Test whether truncl() is declared.
AC_CHECK_DECLS([truncl], , , [[#include <math.h>]])
if test "$ac_cv_have_decl_truncl" = yes; then
dnl Test whether truncl() can be used without libm.
TRUNCL_LIBM=?
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (*funcptr) (long double) = truncl;
long double x;]],
[[x = funcptr(x) + truncl(x);]])],
[TRUNCL_LIBM=])
if test "$TRUNCL_LIBM" = "?"; then
saved_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>
long double (*funcptr) (long double) = truncl;
long double x;]],
[[x = funcptr(x) + truncl(x);]])],
[TRUNCL_LIBM="-lm"])
LIBS="$saved_LIBS"
fi
if test "$TRUNCL_LIBM" = "?"; then
TRUNCL_LIBM=
fi
m4_ifdef([gl_FUNC_TRUNCL_IEEE], [
if test $gl_truncl_required = ieee; then
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether truncl works according to ISO C 99 with IEC 60559],
[gl_cv_func_truncl_ieee],
[
saved_LIBS="$LIBS"
LIBS="$LIBS $TRUNCL_LIBM"
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
]gl_LONG_DOUBLE_SIGNBIT_CODE[
static long double dummy (long double f) { return 0; }
int main (int argc, char *argv[])
{
long double (* volatile my_truncl) (long double) = argc ? truncl : dummy;
/* Test whether truncl (-0.3L) is -0.0L. */
if (signbitl (minus_zerol) && !signbitl (my_truncl (-0.3L)))
return 1;
return 0;
}
]])],
[gl_cv_func_truncl_ieee=yes],
[gl_cv_func_truncl_ieee=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_truncl_ieee="guessing yes" ;;
# Guess yes on musl systems.
*-musl* | midipix*) gl_cv_func_truncl_ieee="guessing yes" ;;
# Guess yes on native Windows.
mingw* | windows*) gl_cv_func_truncl_ieee="guessing yes" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_truncl_ieee="$gl_cross_guess_normal" ;;
esac
])
LIBS="$saved_LIBS"
])
case "$gl_cv_func_truncl_ieee" in
*yes) ;;
*) REPLACE_TRUNCL=1 ;;
esac
fi
])
else
HAVE_DECL_TRUNCL=0
fi
if test $HAVE_DECL_TRUNCL = 0 || test $REPLACE_TRUNCL = 1; then
dnl Find libraries needed to link lib/truncl.c.
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
AC_REQUIRE([gl_FUNC_TRUNC])
TRUNCL_LIBM="$TRUNC_LIBM"
else
TRUNCL_LIBM=
fi
fi
AC_SUBST([TRUNCL_LIBM])
])
|
