136 lines
3.9 KiB
Plaintext
136 lines
3.9 KiB
Plaintext
# ldexpl.m4 serial 17
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dnl Copyright (C) 2007-2018 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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AC_DEFUN([gl_FUNC_LDEXPL],
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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([gl_FUNC_ISNANL]) dnl for ISNANL_LIBM
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dnl Persuade glibc <math.h> to declare ldexpl().
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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dnl Check whether it's declared.
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dnl Mac OS X 10.3 has ldexpl() in libc but doesn't declare it in <math.h>.
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AC_CHECK_DECL([ldexpl], , [HAVE_DECL_LDEXPL=0], [[#include <math.h>]])
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LDEXPL_LIBM=
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if test $HAVE_DECL_LDEXPL = 1; then
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gl_CHECK_LDEXPL_NO_LIBM
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if test $gl_cv_func_ldexpl_no_libm = no; then
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AC_CACHE_CHECK([whether ldexpl() can be used with libm],
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[gl_cv_func_ldexpl_in_libm],
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[
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save_LIBS="$LIBS"
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LIBS="$LIBS -lm"
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <math.h>
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long double x;]],
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[[return ldexpl (x, -1) > 0;]])],
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[gl_cv_func_ldexpl_in_libm=yes],
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[gl_cv_func_ldexpl_in_libm=no])
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LIBS="$save_LIBS"
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])
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if test $gl_cv_func_ldexpl_in_libm = yes; then
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LDEXPL_LIBM=-lm
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fi
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fi
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if test $gl_cv_func_ldexpl_no_libm = yes \
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|| test $gl_cv_func_ldexpl_in_libm = yes; then
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save_LIBS="$LIBS"
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LIBS="$LIBS $LDEXPL_LIBM"
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gl_FUNC_LDEXPL_WORKS
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LIBS="$save_LIBS"
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case "$gl_cv_func_ldexpl_works" in
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*yes) gl_func_ldexpl=yes ;;
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*) gl_func_ldexpl=no; REPLACE_LDEXPL=1 ;;
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esac
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else
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gl_func_ldexpl=no
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fi
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if test $gl_func_ldexpl = yes; then
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AC_DEFINE([HAVE_LDEXPL], [1],
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[Define if the ldexpl() function is available.])
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fi
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fi
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if test $HAVE_DECL_LDEXPL = 0 || test $gl_func_ldexpl = no; then
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dnl Find libraries needed to link lib/ldexpl.c.
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if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
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AC_REQUIRE([gl_FUNC_LDEXP])
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LDEXPL_LIBM="$LDEXP_LIBM"
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else
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LDEXPL_LIBM="$ISNANL_LIBM"
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fi
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fi
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AC_SUBST([LDEXPL_LIBM])
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])
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dnl Test whether ldexpl() can be used without linking with libm.
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dnl Set gl_cv_func_ldexpl_no_libm to 'yes' or 'no' accordingly.
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AC_DEFUN([gl_CHECK_LDEXPL_NO_LIBM],
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[
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AC_CACHE_CHECK([whether ldexpl() can be used without linking with libm],
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[gl_cv_func_ldexpl_no_libm],
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[
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <math.h>
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long double x;]],
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[[return ldexpl (x, -1) > 0;]])],
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[gl_cv_func_ldexpl_no_libm=yes],
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[gl_cv_func_ldexpl_no_libm=no])
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])
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])
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dnl Test whether ldexpl() works on finite numbers (this fails on AIX 5.1
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dnl and Mac OS X 10.4/PowerPC).
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AC_DEFUN([gl_FUNC_LDEXPL_WORKS],
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[
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AC_REQUIRE([AC_PROG_CC])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether ldexpl works], [gl_cv_func_ldexpl_works],
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[
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AC_RUN_IFELSE(
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[AC_LANG_SOURCE([[
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#include <math.h>
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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 ldexpl (long double, int);
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int main()
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{
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int result = 0;
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{
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volatile long double x = 1.0;
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volatile long double y = ldexpl (x, -1);
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if (y != 0.5L)
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result |= 1;
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}
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{
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volatile long double x = 1.73205L;
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volatile long double y = ldexpl (x, 0);
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if (y != x)
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result |= 2;
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}
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return result;
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}]])],
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[gl_cv_func_ldexpl_works=yes],
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[gl_cv_func_ldexpl_works=no],
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[
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changequote(,)dnl
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case "$host_os" in
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aix | aix[3-6]*) gl_cv_func_ldexpl_works="guessing no" ;;
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# Guess yes on native Windows.
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mingw*) gl_cv_func_ldexpl_works="guessing yes" ;;
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*) gl_cv_func_ldexpl_works="guessing yes" ;;
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esac
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changequote([,])dnl
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])
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])
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])
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