-# truncf.m4 serial 3
-dnl Copyright (C) 2007, 2010 Free Software Foundation, Inc.
+# truncf.m4 serial 8
+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_TRUNCF],
[
+ m4_divert_text([DEFAULTS], [gl_truncf_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
dnl Persuade glibc <math.h> to declare truncf().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Test whether truncf() is declared.
- AC_CHECK_DECLS([truncf], , , [#include <math.h>])
+ AC_CHECK_DECLS([truncf], , , [[#include <math.h>]])
if test "$ac_cv_have_decl_truncf" = yes; then
dnl Test whether truncf() can be used without libm.
TRUNCF_LIBM=?
if test "$TRUNCF_LIBM" = "?"; then
TRUNCF_LIBM=
fi
+ m4_ifdef([gl_FUNC_TRUNCF_IEEE], [
+ if test $gl_truncf_required = ieee && test $REPLACE_TRUNCF = 0; then
+ AC_CACHE_CHECK([whether truncf works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_truncf_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $TRUNCF_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+ float (*my_truncf) (float) = argc ? truncf : dummy;
+ /* Test whether truncf (-0.0f) is -0.0f. */
+ if (signbitf (minus_zerof) && !signbitf (my_truncf (minus_zerof)))
+ return 1;
+ return 0;
+}
+ ]])],
+ [gl_cv_func_truncf_ieee=yes],
+ [gl_cv_func_truncf_ieee=no],
+ [gl_cv_func_truncf_ieee="guessing no"])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_truncf_ieee" in
+ *yes) ;;
+ *) REPLACE_TRUNCF=1 ;;
+ esac
+ fi
+ ])
else
HAVE_DECL_TRUNCF=0
- AC_LIBOBJ([truncf])
+ fi
+ if test $HAVE_DECL_TRUNCF = 0 || test $REPLACE_TRUNCF = 1; then
+ dnl No libraries are needed to link lib/truncf.c.
TRUNCF_LIBM=
fi
AC_SUBST([TRUNCF_LIBM])