X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffloor.m4;h=568310785b7ce605d2d7ab37eff45642dec2a31e;hb=12856373f8fd28a9d4453d6df97b2fdd17ced398;hp=780a88fbf1dbbaeb46252370a48bb495ed39f199;hpb=1fd8064a06ed3ca83f73c495e998e66c225e395b;p=gnulib.git

diff --git a/m4/floor.m4 b/m4/floor.m4
index 780a88fbf..568310785 100644
--- a/m4/floor.m4
+++ b/m4/floor.m4
@@ -1,16 +1,56 @@
-# floor.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# floor.m4 serial 5
+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_FLOOR],
 [
+  m4_divert_text([DEFAULTS], [gl_floor_required=plain])
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Test whether floor() can be used without libm.
   gl_FUNC_FLOOR_LIBS
   if test "$FLOOR_LIBM" = "?"; then
     FLOOR_LIBM=
   fi
+  m4_ifdef([gl_FUNC_FLOOR_IEEE], [
+    if test $gl_floor_required = ieee && test $REPLACE_FLOOR = 0; then
+      AC_CACHE_CHECK([whether floor works according to ISO C 99 with IEC 60559],
+        [gl_cv_func_floor_ieee],
+        [
+          save_LIBS="$LIBS"
+          LIBS="$LIBS $FLOOR_LIBM"
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_DOUBLE_MINUS_ZERO_CODE[
+]gl_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether floor (-0.0) is -0.0.  */
+  if (signbitd (minus_zerod) && !signbitd (floor (minus_zerod)))
+    return 1;
+  return 0;
+}
+            ]])],
+            [gl_cv_func_floor_ieee=yes],
+            [gl_cv_func_floor_ieee=no],
+            [gl_cv_func_floor_ieee="guessing no"])
+          LIBS="$save_LIBS"
+        ])
+      case "$gl_cv_func_floor_ieee" in
+        *yes) ;;
+        *) REPLACE_FLOOR=1 ;;
+      esac
+    fi
+  ])
+  if test $REPLACE_FLOOR = 1; then
+    AC_LIBOBJ([floor])
+    FLOOR_LIBM=
+  fi
   AC_SUBST([FLOOR_LIBM])
 ])
 
@@ -18,29 +58,31 @@ AC_DEFUN([gl_FUNC_FLOOR],
 # Sets FLOOR_LIBM.
 AC_DEFUN([gl_FUNC_FLOOR_LIBS],
 [
-  AC_CACHE_VAL([gl_func_floor_libm], [
-    gl_func_floor_libm=?
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       double x;],
-      [x = floor(x);],
-      [gl_func_floor_libm=])
-    if test "$gl_func_floor_libm" = "?"; then
+  gl_CACHE_VAL_SILENT([gl_cv_func_floor_libm], [
+    gl_cv_func_floor_libm=?
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           double x;]],
+         [[x = floor(x);]])],
+      [gl_cv_func_floor_libm=])
+    if test "$gl_cv_func_floor_libm" = "?"; then
       save_LIBS="$LIBS"
       LIBS="$LIBS -lm"
-      AC_TRY_LINK([
-         #ifndef __NO_MATH_INLINES
-         # define __NO_MATH_INLINES 1 /* for glibc */
-         #endif
-         #include <math.h>
-         double x;],
-        [x = floor(x);],
-        [gl_func_floor_libm="-lm"])
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             double x;]],
+           [[x = floor(x);]])],
+        [gl_cv_func_floor_libm="-lm"])
       LIBS="$save_LIBS"
     fi
   ])
-  FLOOR_LIBM="$gl_func_floor_libm"
+  FLOOR_LIBM="$gl_cv_func_floor_libm"
 ])