-# trunc.m4 serial 4
-dnl Copyright (C) 2007, 2010 Free Software Foundation, Inc.
+# trunc.m4 serial 5
+dnl Copyright (C) 2007, 2010-2011 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_TRUNC],
[
+ m4_divert_text([DEFAULTS], [gl_trunc_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
dnl Persuade glibc <math.h> to declare trunc().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
if test "$TRUNC_LIBM" = "?"; then
TRUNC_LIBM=
fi
+ m4_ifdef([gl_FUNC_TRUNC_IEEE], [
+ if test $gl_trunc_required = ieee && test $REPLACE_TRUNC = 0; then
+ AC_CACHE_CHECK([whether trunc works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_trunc_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $TRUNC_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_DOUBLE_MINUS_ZERO_CODE[
+]gl_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+ /* Test whether trunc (-0.0) is -0.0. */
+ if (signbitd (minus_zerod) && !signbitd (trunc (minus_zerod)))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_trunc_ieee=yes],
+ [gl_cv_func_trunc_ieee=no],
+ [gl_cv_func_trunc_ieee="guessing no"])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_trunc_ieee" in
+ *yes) ;;
+ *) REPLACE_TRUNC=1 ;;
+ esac
+ fi
+ ])
else
HAVE_DECL_TRUNC=0
+ fi
+ if test $HAVE_DECL_TRUNC = 0 || test $REPLACE_TRUNC = 1; then
AC_LIBOBJ([trunc])
TRUNC_LIBM=
fi