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# expl.m4 serial 8
dnl Copyright (C) 2010-2017 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])
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 (*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="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#ifndef __NO_MATH_INLINES
# define __NO_MATH_INLINES 1 /* for glibc */
#endif
#include <math.h>
long double (*funcptr) (long double) = expl;
long double x;]],
[[return funcptr (x) > 1.5
|| expl (x) > 1.5;]])],
[gl_cv_func_expl_in_libm=yes],
[gl_cv_func_expl_in_libm=no])
LIBS="$save_LIBS"
])
if test $gl_cv_func_expl_in_libm = yes; then
EXPL_LIBM=-lm
fi
fi
dnl On OpenBSD5.4 the system's native expl() is buggy:
dnl it returns 'nan' for small values. Test for this anomaly.
if test $gl_cv_func_expl_no_libm = yes \
|| test $gl_cv_func_expl_in_libm = yes; then
AC_CACHE_CHECK([whether expl() breaks with small values],
[gl_cv_func_expl_buggy],
[
save_LIBS="$LIBS"
LIBS="$EXPL_LIBM"
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>]],
[[return isnan(expl(-1.0))||
isnan(expl(-0.8))||
isnan(expl(-0.4)); ]])],
[gl_cv_func_expl_buggy=no], [gl_cv_func_expl_buggy=yes],
[case $host_os in
openbsd*) gl_cv_func_expl_buggy="guessing yes";;
*) gl_cv_func_expl_buggy="guessing no";;
esac])
LIBS="$save_LIBS"
])
case "$gl_cv_func_expl_buggy" in
*yes)
gl_cv_func_expl_in_libm=no
gl_cv_func_expl_no_libm=no ;;
esac
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>]])
else
HAVE_DECL_EXPL=0
HAVE_EXPL=0
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])
])
|
