X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Froundl.m4;h=eece9d7cb302ae4cdbfb4a602fedb80e3858f9b5;hb=21492d6c3ca00ff0827528640804732f2ed66470;hp=de9f63a0f0d3cdfda54321f8a3d86b8886e074ea;hpb=13314b446d38305438b86c5baafe72395376e310;p=gnulib.git

diff --git a/m4/roundl.m4 b/m4/roundl.m4
index de9f63a0f..eece9d7cb 100644
--- a/m4/roundl.m4
+++ b/m4/roundl.m4
@@ -1,30 +1,85 @@
-# roundl.m4 serial 4
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# roundl.m4 serial 12
+dnl Copyright (C) 2007, 2009-2011 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_ROUNDL],
 [
+  m4_divert_text([DEFAULTS], [gl_roundl_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare roundl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
-  AC_CHECK_DECLS([roundl], , , [#include <math.h>])
+  AC_CHECK_DECLS([roundl], , , [[#include <math.h>]])
   if test "$ac_cv_have_decl_roundl" = yes; then
     gl_CHECK_MATH_LIB([ROUNDL_LIBM], [x = roundl (x);])
+    if test "$ROUNDL_LIBM" = missing; then
+      REPLACE_ROUNDL=1
+    fi
+    m4_ifdef([gl_FUNC_ROUNDL_IEEE], [
+      if test $gl_roundl_required = ieee && test $REPLACE_ROUNDL = 0; then
+        AC_CACHE_CHECK([whether roundl works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_roundl_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $ROUNDL_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+static long double dummy (long double f) { return 0; }
+int main (int argc, char *argv[])
+{
+  long double (*my_roundl) (long double) = argc ? roundl : dummy;
+  int result = 0;
+  /* Test whether roundl (-0.0L) is -0.0L.  */
+  if (signbitl (minus_zerol) && !signbitl (my_roundl (minus_zerol)))
+    result |= 1;
+  /* Test whether roundl (-0.3L) is -0.0L.  */
+  if (signbitl (-0.3L) && !signbitl (my_roundl (-0.3L)))
+    result |= 2;
+  return result;
+}
+              ]])],
+              [gl_cv_func_roundl_ieee=yes],
+              [gl_cv_func_roundl_ieee=no],
+              [gl_cv_func_roundl_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_roundl_ieee" in
+          *yes) ;;
+          *) REPLACE_ROUNDL=1 ;;
+        esac
+      fi
+    ])
+  else
+    HAVE_DECL_ROUNDL=0
   fi
-  if test "$ac_cv_have_decl_roundl" != yes || test "$ROUNDL_LIBM" = missing; then
-    REPLACE_ROUNDL=1
-    AC_LIBOBJ([roundl])
-    AC_CHECK_DECLS([ceill, floorl], , , [#include <math.h>])
+  if test $HAVE_DECL_ROUNDL = 0 || test $REPLACE_ROUNDL = 1; then
+    dnl Find libraries needed to link lib/roundl.c.
+    AC_CHECK_DECLS([ceill, floorl], , , [[#include <math.h>]])
     if test "$ac_cv_have_decl_floorl" = yes \
        && test "$ac_cv_have_decl_ceill" = yes; then
       gl_FUNC_FLOORL_LIBS
       gl_FUNC_CEILL_LIBS
       if test "$FLOORL_LIBM" != '?' && test "$CEILL_LIBM" != '?'; then
-        AC_DEFINE([HAVE_FLOORL_AND_CEILL], 1,
+        AC_DEFINE([HAVE_FLOORL_AND_CEILL], [1],
           [Define if the both the floorl() and ceill() functions exist.])
-        ROUNDL_LIBM="$FLOORL_LIBM $CEILL_LIBM"
+        ROUNDL_LIBM=
+        dnl Append $FLOORL_LIBM to ROUNDL_LIBM, avoiding gratuitous duplicates.
+        case " $ROUNDL_LIBM " in
+          *" $FLOORL_LIBM "*) ;;
+          *) ROUNDL_LIBM="$ROUNDL_LIBM $FLOORL_LIBM" ;;
+        esac
+        dnl Append $CEILL_LIBM to ROUNDL_LIBM, avoiding gratuitous duplicates.
+        case " $ROUNDL_LIBM " in
+          *" $CEILL_LIBM "*) ;;
+          *) ROUNDL_LIBM="$ROUNDL_LIBM $CEILL_LIBM" ;;
+        esac
       else
         ROUNDL_LIBM=
       fi