203 lines
6.7 KiB
Plaintext
203 lines
6.7 KiB
Plaintext
# expl.m4
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# serial 22
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dnl Copyright (C) 2010-2024 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl This file is offered as-is, without any warranty.
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AC_DEFUN([gl_FUNC_EXPL],
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[
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AC_REQUIRE([gl_MATH_H_DEFAULTS])
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AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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dnl Persuade glibc <math.h> to declare expl().
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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EXPL_LIBM=
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AC_CACHE_CHECK([whether expl() can be used without linking with libm],
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[gl_cv_func_expl_no_libm],
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[
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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long double (* volatile funcptr) (long double) = expl;
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long double x;]],
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[[return funcptr (x) > 1.5
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|| expl (x) > 1.5;]])],
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[gl_cv_func_expl_no_libm=yes],
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[gl_cv_func_expl_no_libm=no])
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])
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if test $gl_cv_func_expl_no_libm = no; then
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AC_CACHE_CHECK([whether expl() can be used with libm],
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[gl_cv_func_expl_in_libm],
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[
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saved_LIBS="$LIBS"
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LIBS="$LIBS -lm"
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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long double (* volatile funcptr) (long double) = expl;
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long double x;]],
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[[return funcptr (x) > 1.5
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|| expl (x) > 1.5;]])],
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[gl_cv_func_expl_in_libm=yes],
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[gl_cv_func_expl_in_libm=no])
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LIBS="$saved_LIBS"
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])
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if test $gl_cv_func_expl_in_libm = yes; then
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EXPL_LIBM=-lm
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fi
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fi
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if test $gl_cv_func_expl_no_libm = yes \
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|| test $gl_cv_func_expl_in_libm = yes; then
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dnl Also check whether it's declared.
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dnl Mac OS X 10.3 has expl() in libc but doesn't declare it in <math.h>.
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AC_CHECK_DECL([expl], , [HAVE_DECL_EXPL=0], [[#include <math.h>]])
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if test $REPLACE_EXPL = 0; then
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether expl works],
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[gl_cv_func_expl_works],
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[
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saved_LIBS="$LIBS"
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LIBS="$LIBS $EXPL_LIBM"
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AC_RUN_IFELSE(
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[AC_LANG_SOURCE([[
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#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <float.h>
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#include <math.h>
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/* Override the values of <float.h>, like done in float.in.h. */
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#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
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# undef LDBL_MANT_DIG
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# define LDBL_MANT_DIG 64
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# undef LDBL_MIN_EXP
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# define LDBL_MIN_EXP (-16381)
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# undef LDBL_MAX_EXP
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# define LDBL_MAX_EXP 16384
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#endif
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#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
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# undef LDBL_MANT_DIG
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# define LDBL_MANT_DIG 64
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# undef LDBL_MIN_EXP
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# define LDBL_MIN_EXP (-16381)
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# undef LDBL_MAX_EXP
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# define LDBL_MAX_EXP 16384
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#endif
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#if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
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# undef LDBL_MIN_EXP
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# define LDBL_MIN_EXP DBL_MIN_EXP
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#endif
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#if defined __sgi && (LDBL_MANT_DIG >= 106)
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# undef LDBL_MANT_DIG
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# define LDBL_MANT_DIG 106
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# if defined __GNUC__
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# undef LDBL_MIN_EXP
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# define LDBL_MIN_EXP DBL_MIN_EXP
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# endif
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#endif
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#undef expl
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extern
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#ifdef __cplusplus
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"C"
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#endif
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long double expl (long double);
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static long double dummy (long double x) { return 0; }
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int main (int argc, char *argv[])
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{
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long double (* volatile my_expl) (long double) = argc ? expl : dummy;
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int result = 0;
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/* On Haiku 2017 the system's native expl() is just a stub: it returns 0.0
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and prints "__expl not implemented" for all arguments. */
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{
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volatile long double x1 = -1.0;
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if (expl (x1) == 0.0)
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result |= 1;
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}
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/* On OpenBSD 5.4 the system's native expl() is buggy:
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it returns 'nan' for small values. */
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{
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volatile long double x1 = -1.0;
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volatile long double x2 = -0.8;
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volatile long double x3 = -0.4;
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if (isnan (expl (x1)) || isnan (expl (x2)) || isnan (expl (x3)))
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result |= 2;
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}
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/* This test fails on musl 1.2.2/arm64, musl 1.2.2/s390x, NetBSD 9.3. */
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{
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const long double TWO_LDBL_MANT_DIG = /* 2^LDBL_MANT_DIG */
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(long double) (1U << ((LDBL_MANT_DIG - 1) / 5))
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* (long double) (1U << ((LDBL_MANT_DIG - 1 + 1) / 5))
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* (long double) (1U << ((LDBL_MANT_DIG - 1 + 2) / 5))
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* (long double) (1U << ((LDBL_MANT_DIG - 1 + 3) / 5))
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* (long double) (1U << ((LDBL_MANT_DIG - 1 + 4) / 5));
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long double x = 11.358L;
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long double err = (my_expl (x) * my_expl (- x) - 1.0L) * TWO_LDBL_MANT_DIG;
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if (!(err >= -100.0L && err <= 100.0L))
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result |= 4;
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}
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return result;
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}
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]])],
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[gl_cv_func_expl_works=yes],
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[gl_cv_func_expl_works=no],
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[case "$host_os" in
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# Guess yes on glibc systems.
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*-gnu* | gnu*) gl_cv_func_expl_works="guessing yes" ;;
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# Guess no on musl systems.
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*-musl* | midipix*) gl_cv_func_expl_works="guessing no" ;;
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# Guess yes on native Windows.
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mingw* | windows*) gl_cv_func_expl_works="guessing yes" ;;
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# If we don't know, obey --enable-cross-guesses.
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*) gl_cv_func_expl_works="$gl_cross_guess_normal" ;;
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esac
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])
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LIBS="$saved_LIBS"
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])
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case "$gl_cv_func_expl_works" in
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*yes) ;;
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*) REPLACE_EXPL=1 ;;
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esac
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fi
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else
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HAVE_DECL_EXPL=0
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HAVE_EXPL=0
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fi
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if test $HAVE_EXPL = 0 || test $REPLACE_EXPL = 1; then
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dnl Find libraries needed to link lib/expl.c.
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if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
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AC_REQUIRE([gl_FUNC_EXP])
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EXPL_LIBM="$EXP_LIBM"
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else
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AC_REQUIRE([gl_FUNC_ISNANL])
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AC_REQUIRE([gl_FUNC_ROUNDL])
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AC_REQUIRE([gl_FUNC_LDEXPL])
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EXPL_LIBM=
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dnl Append $ISNANL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
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case " $EXPL_LIBM " in
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*" $ISNANL_LIBM "*) ;;
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*) EXPL_LIBM="$EXPL_LIBM $ISNANL_LIBM" ;;
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esac
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dnl Append $ROUNDL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
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case " $EXPL_LIBM " in
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*" $ROUNDL_LIBM "*) ;;
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*) EXPL_LIBM="$EXPL_LIBM $ROUNDL_LIBM" ;;
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esac
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dnl Append $LDEXPL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
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case " $EXPL_LIBM " in
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*" $LDEXPL_LIBM "*) ;;
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*) EXPL_LIBM="$EXPL_LIBM $LDEXPL_LIBM" ;;
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esac
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fi
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fi
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AC_SUBST([EXPL_LIBM])
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])
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