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