-# modff.m4 serial 1
-dnl Copyright (C) 2011 Free Software Foundation, Inc.
+# modff.m4 serial 5
+dnl Copyright (C) 2011-2013 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_MODFF],
[
+ m4_divert_text([DEFAULTS], [gl_modff_required=plain])
AC_REQUIRE([gl_MATH_H_DEFAULTS])
AC_REQUIRE([gl_FUNC_MODF])
- dnl Test whether modff() exists. Assume that modff(), if it exists, is
- dnl defined in the same library as modf().
- save_LIBS="$LIBS"
- LIBS="$LIBS $MODF_LIBM"
- AC_CHECK_FUNCS([modff])
- LIBS="$save_LIBS"
- if test $ac_cv_func_modff = yes; then
- MODFF_LIBM="$MODF_LIBM"
+ dnl Persuade glibc <math.h> to declare modff().
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+ dnl Test whether modff() exists. We cannot assume that modff(), if it
+ dnl exists, is defined in the same library as modf(). This is not the case
+ dnl on FreeBSD, NetBSD, OpenBSD.
+ gl_MATHFUNC([modff], [float], [(float, float *)])
+ if test $gl_cv_func_modff_no_libm = yes \
+ || test $gl_cv_func_modff_in_libm = yes; then
+ :
+ m4_ifdef([gl_FUNC_MODFF_IEEE], [
+ if test $gl_modff_required = ieee && test $REPLACE_MODFF = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether modff works according to ISO C 99 with IEC 60559],
+ [gl_cv_func_modff_ieee],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $MODFF_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+/* Compare two numbers with ==.
+ This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+ 'x == x' test. */
+static int
+numeric_equal (float x, float y)
+{
+ return x == y;
+}
+static float dummy (float x, float *iptr) { return 0; }
+float zero;
+float minus_one = - 1.0f;
+int main (int argc, char *argv[])
+{
+ float (*my_modff) (float, float *) = argc ? modff : dummy;
+ int result = 0;
+ float i;
+ float f;
+ /* Test modff(NaN,...).
+ This test fails on NetBSD 5.1, OpenBSD 4.9, Solaris 9, Cygwin. */
+ f = my_modff (zero / zero, &i);
+ if (numeric_equal (f, f))
+ result |= 1;
+ /* Test modff(-Inf,...).
+ This test fails on IRIX 6.5, OSF/1 5.1, mingw. */
+ f = my_modff (minus_one / zero, &i);
+ if (!(f == 0.0f) || (signbitf (minus_zerof) && !signbitf (f)))
+ result |= 2;
+ return result;
+}
+ ]])],
+ [gl_cv_func_modff_ieee=yes],
+ [gl_cv_func_modff_ieee=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_modff_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_modff_ieee="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_modff_ieee" in
+ *yes) ;;
+ *) REPLACE_MODFF=1 ;;
+ esac
+ fi
+ ])
else
HAVE_MODFF=0
+ fi
+ if test $HAVE_MODFF = 0 || test $REPLACE_MODFF = 1; then
+ dnl Find libraries needed to link lib/modff.c.
MODFF_LIBM="$MODF_LIBM"
fi
AC_SUBST([MODFF_LIBM])