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|
# expl.m4 serial 19
dnl Copyright (C) 2010-2023 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_EXPL],
[
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 expl().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
EXPL_LIBM=
AC_CACHE_CHECK([whether expl() can be used without linking with libm],
[gl_cv_func_expl_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (* volatile funcptr) (long double) = expl;
long double x;]],
[[return funcptr (x) > 1.5
|| expl (x) > 1.5;]])],
[gl_cv_func_expl_no_libm=yes],
[gl_cv_func_expl_no_libm=no])
])
if test $gl_cv_func_expl_no_libm = no; then
AC_CACHE_CHECK([whether expl() can be used with libm],
[gl_cv_func_expl_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (* volatile funcptr) (long double) = expl;
long double x;]],
[[return funcptr (x) > 1.5
|| expl (x) > 1.5;]])],
[gl_cv_func_expl_in_libm=yes],
[gl_cv_func_expl_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_expl_in_libm = yes; then
EXPL_LIBM=-lm
fi
fi
if test $gl_cv_func_expl_no_libm = yes \
|| test $gl_cv_func_expl_in_libm = yes; then
dnl Also check whether it's declared.
dnl Mac OS X 10.3 has expl() in libc but doesn't declare it in <math.h>.
AC_CHECK_DECL([expl], , [HAVE_DECL_EXPL=0], [[#include <math.h>]])
if test $REPLACE_EXPL = 0; then
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether expl works],
[gl_cv_func_expl_works],
[
save_LIBS="$LIBS"
LIBS="$LIBS $EXPL_LIBM"
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#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_MANT_DIG
# define LDBL_MANT_DIG 64
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP (-16381)
# undef LDBL_MAX_EXP
# define LDBL_MAX_EXP 16384
#endif
#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
# undef LDBL_MANT_DIG
# define LDBL_MANT_DIG 64
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP (-16381)
# undef LDBL_MAX_EXP
# define LDBL_MAX_EXP 16384
#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)
# undef LDBL_MANT_DIG
# define LDBL_MANT_DIG 106
# if defined __GNUC__
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP DBL_MIN_EXP
# endif
#endif
#undef expl
extern
#ifdef __cplusplus
"C"
#endif
long double expl (long double);
static long double dummy (long double x) { return 0; }
int main (int argc, char *argv[])
{
long double (* volatile my_expl) (long double) = argc ? expl : dummy;
int result = 0;
/* On Haiku 2017 the system's native expl() is just a stub: it returns 0.0
and prints "__expl not implemented" for all arguments. */
{
volatile long double x1 = -1.0;
if (expl (x1) == 0.0)
result |= 1;
}
/* On OpenBSD 5.4 the system's native expl() is buggy:
it returns 'nan' for small values. */
{
volatile long double x1 = -1.0;
volatile long double x2 = -0.8;
volatile long double x3 = -0.4;
if (isnan (expl (x1)) || isnan (expl (x2)) || isnan (expl (x3)))
result |= 2;
}
/* This test fails on musl 1.2.2/arm64, musl 1.2.2/s390x, NetBSD 9.0. */
{
const long double TWO_LDBL_MANT_DIG = /* 2^LDBL_MANT_DIG */
(long double) (1U << ((LDBL_MANT_DIG - 1) / 5))
* (long double) (1U << ((LDBL_MANT_DIG - 1 + 1) / 5))
* (long double) (1U << ((LDBL_MANT_DIG - 1 + 2) / 5))
* (long double) (1U << ((LDBL_MANT_DIG - 1 + 3) / 5))
* (long double) (1U << ((LDBL_MANT_DIG - 1 + 4) / 5));
long double x = 11.358L;
long double err = (my_expl (x) * my_expl (- x) - 1.0L) * TWO_LDBL_MANT_DIG;
if (!(err >= -100.0L && err <= 100.0L))
result |= 4;
}
return result;
}
]])],
[gl_cv_func_expl_works=yes],
[gl_cv_func_expl_works=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_expl_works="guessing yes" ;;
# Guess no on musl systems.
*-musl* | midipix*) gl_cv_func_expl_works="guessing no" ;;
# Guess yes on native Windows.
mingw*) gl_cv_func_expl_works="guessing yes" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_expl_works="$gl_cross_guess_normal" ;;
esac
])
LIBS="$save_LIBS"
])
case "$gl_cv_func_expl_works" in
*yes) ;;
*) REPLACE_EXPL=1 ;;
esac
fi
else
HAVE_DECL_EXPL=0
HAVE_EXPL=0
fi
if test $HAVE_EXPL = 0 || test $REPLACE_EXPL = 1; then
dnl Find libraries needed to link lib/expl.c.
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
AC_REQUIRE([gl_FUNC_EXP])
EXPL_LIBM="$EXP_LIBM"
else
AC_REQUIRE([gl_FUNC_ISNANL])
AC_REQUIRE([gl_FUNC_ROUNDL])
AC_REQUIRE([gl_FUNC_LDEXPL])
EXPL_LIBM=
dnl Append $ISNANL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
case " $EXPL_LIBM " in
*" $ISNANL_LIBM "*) ;;
*) EXPL_LIBM="$EXPL_LIBM $ISNANL_LIBM" ;;
esac
dnl Append $ROUNDL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
case " $EXPL_LIBM " in
*" $ROUNDL_LIBM "*) ;;
*) EXPL_LIBM="$EXPL_LIBM $ROUNDL_LIBM" ;;
esac
dnl Append $LDEXPL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
case " $EXPL_LIBM " in
*" $LDEXPL_LIBM "*) ;;
*) EXPL_LIBM="$EXPL_LIBM $LDEXPL_LIBM" ;;
esac
fi
fi
AC_SUBST([EXPL_LIBM])
])
|
