X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fceill.m4;h=71ac74fc20af297838ee1c05e2f5f5de789294c4;hb=f05c2e5860d43cf3d44fc69218629ddde2ee7277;hp=02527799cfcc7ccdfa0a2c7161042b3cee690ac0;hpb=93c5ec22b9dcc15031556d647b5450fa6e645c21;p=gnulib.git

diff --git a/m4/ceill.m4 b/m4/ceill.m4
index 02527799c..71ac74fc2 100644
--- a/m4/ceill.m4
+++ b/m4/ceill.m4
@@ -1,11 +1,12 @@
-# ceill.m4 serial 5
-dnl Copyright (C) 2007, 2009-2010 Free Software Foundation, Inc.
+# ceill.m4 serial 8
+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_CEILL],
 [
+  m4_divert_text([DEFAULTS], [gl_ceill_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare ceill().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
@@ -19,10 +20,44 @@ AC_DEFUN([gl_FUNC_CEILL],
       dnl libm.so, but not in the libm.so that the compiler uses.
       REPLACE_CEILL=1
     fi
+    m4_ifdef([gl_FUNC_CEILL_IEEE], [
+      if test $gl_ceill_required = ieee && test $REPLACE_CEILL = 0; then
+        AC_CACHE_CHECK([whether ceill works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_ceill_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $CEILL_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
+]gl_LONG_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether ceill (-0.3L) is -0.0L.  */
+  if (signbitl (minus_zerol) && !signbitl (ceill (-0.3L)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_ceill_ieee=yes],
+              [gl_cv_func_ceill_ieee=no],
+              [gl_cv_func_ceill_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_ceill_ieee" in
+          *yes) ;;
+          *) REPLACE_CEILL=1 ;;
+        esac
+      fi
+    ])
   else
-    REPLACE_CEILL=1
+    HAVE_DECL_CEILL=0
   fi
-  if test $REPLACE_CEILL = 1; then
+  if test $HAVE_DECL_CEILL = 0 || test $REPLACE_CEILL = 1; then
     AC_LIBOBJ([ceill])
     CEILL_LIBM=
   fi
@@ -35,24 +70,26 @@ AC_DEFUN([gl_FUNC_CEILL_LIBS],
 [
   gl_CACHE_VAL_SILENT([gl_cv_func_ceill_libm], [
     gl_cv_func_ceill_libm=?
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       long double x;],
-      [x = ceill(x);],
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           long double x;]],
+         [[x = ceill(x);]])],
       [gl_cv_func_ceill_libm=])
     if test "$gl_cv_func_ceill_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>
-         long double x;],
-        [x = ceill(x);],
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             long double x;]],
+           [[x = ceill(x);]])],
         [gl_cv_func_ceill_libm="-lm"])
       LIBS="$save_LIBS"
     fi