maint: update all copyright year number ranges

[gnulib.git] / m4 / modfl.m4

diff --git a/m4/modfl.m4 b/m4/modfl.m4
index 98aa363..a7e1475 100644 (file)
--- a/m4/modfl.m4
+++ b/m4/modfl.m4
@@ -1,21 +1,87 @@
-# modfl.m4 serial 1
-dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
+# modfl.m4 serial 3
+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_MODFL],
 [
+  m4_divert_text([DEFAULTS], [gl_modfl_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
 
+  dnl Persuade glibc <math.h> to declare modfl().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Test whether modfl() exists. We cannot assume that modfl(), if it
   dnl exists, is defined in the same library as modf(). This is not the case
   dnl on FreeBSD, Solaris.
   gl_MATHFUNC([modfl], [long double], [(long double, long double *)])
-  if test $gl_cv_func_modfl_no_libm = no \
-     && test $gl_cv_func_modfl_in_libm = no; then
+  if test $gl_cv_func_modfl_no_libm = yes \
+     || test $gl_cv_func_modfl_in_libm = yes; then
+    :
+    m4_ifdef([gl_FUNC_MODFL_IEEE], [
+      if test $gl_modfl_required = ieee && test $REPLACE_MODFL = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+        AC_CACHE_CHECK([whether modfl works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_modfl_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $MODFL_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+/* Compare two numbers with ==.
+   This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+   'x == x' test.  */
+static int
+numeric_equal (long double x, long double y)
+{
+  return x == y;
+}
+static long double dummy (long double x, long double *iptr) { return 0; }
+long double zero;
+long double minus_one = - 1.0L;
+int main (int argc, char *argv[])
+{
+  long double (*my_modfl) (long double, long double *) = argc ? modfl : dummy;
+  long double i;
+  long double f;
+  /* Test modfl(-Inf,...).
+     This test fails on IRIX 6.5, OSF/1 5.1, mingw.  */
+  f = my_modfl (minus_one / zero, &i);
+  if (!(f == 0.0L) || (signbitl (minus_zerol) && !signbitl (f)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_modfl_ieee=yes],
+              [gl_cv_func_modfl_ieee=no],
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_modfl_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_modfl_ieee="guessing no" ;;
+               esac
+              ])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_modfl_ieee" in
+          *yes) ;;
+          *) REPLACE_MODFL=1 ;;
+        esac
+      fi
+    ])
+  else
     HAVE_MODFL=0
+  fi
+  if test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; then
+    dnl Find libraries needed to link lib/modfl.c.
     if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
       AC_REQUIRE([gl_FUNC_MODF])
       MODFL_LIBM="$MODF_LIBM"