--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2010-12-21  Bruno Haible  <bruno@clisp.org>
+
+	New module 'ceil-ieee'.
+	* modules/ceil-ieee: New file.
+	* m4/ceil.m4 (gl_FUNC_CEIL): Require gl_MATH_H_DEFAULTS. If
+	gl_FUNC_CEIL_IEEE is also used, test whether ceil works according to
+	ISO C 99 with IEC 60559.
+	* m4/ceil-ieee.m4: New file.
+	* modules/ceil (Files): Add lib/ceil.c.
+	(Depends-on): Add 'float'.
+	(configure.ac): Invoke gl_MATH_MODULE_INDICATOR.
+	* lib/math.in.h (ceil): New declaration.
+	* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize GNULIB_CEIL,
+	REPLACE_CEIL.
+	* modules/math (Makefile.am): Substitute GNULIB_CEIL, REPLACE_CEIL.
+	* modules/ceil-ieee-tests: New file.
+	* tests/test-ceil-ieee.c: New file, based on tests/test-ceilf-ieee.c.
+	* tests/test-math-c++.cc: Check the signature of 'ceil'.
+	* doc/posix-functions/ceil.texi: Mention the new module.
+
 2010-12-21  Bruno Haible  <bruno@clisp.org>
 
 	New module 'floor-ieee'.

--- a/doc/posix-functions/ceil.texi
+++ b/doc/posix-functions/ceil.texi
@@ -4,10 +4,18 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/ceil.html}
 
-Gnulib module: ceil
+Gnulib module: ceil or ceil-ieee
+
+Portability problems fixed by either Gnulib module @code{ceil} or @code{ceil-ieee}:
+@itemize
+@end itemize
 
-Portability problems fixed by Gnulib:
+Portability problems fixed by Gnulib module @code{ceil-ieee}:
 @itemize
+@item
+This function returns a positive zero for a minus zero argument
+on some platforms:
+OSF/1 5.1.
 @end itemize
 
 Portability problems not fixed by Gnulib:

--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -202,6 +202,19 @@
 # endif
 #endif
 
+#if @GNULIB_CEIL@
+# if @REPLACE_CEIL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define ceil rpl_ceil
+#  endif
+_GL_FUNCDECL_RPL (ceil, double, (double x));
+_GL_CXXALIAS_RPL (ceil, double, (double x));
+# else
+_GL_CXXALIAS_SYS (ceil, double, (double x));
+# endif
+_GL_CXXALIASWARN (ceil);
+#endif
+
 #if @GNULIB_CEILL@
 # if @REPLACE_CEILL@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)

new file mode 100644
--- /dev/null
+++ b/m4/ceil-ieee.m4
@@ -0,0 +1,15 @@
+# ceil-ieee.m4 serial 1
+dnl Copyright (C) 2010 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.
+
+dnl This macro is in a separate file (not in ceil.m4 and not inlined in the
+dnl module description), so that gl_FUNC_CEIL can test whether 'aclocal' has
+dnl found uses of this macro.
+
+AC_DEFUN([gl_FUNC_CEIL_IEEE],
+[
+  m4_divert_text([INIT_PREPARE], [gl_ceil_required=ieee])
+  AC_REQUIRE([gl_FUNC_CEIL])
+])

--- a/m4/ceil.m4
+++ b/m4/ceil.m4
@@ -1,16 +1,56 @@
-# ceil.m4 serial 4
-dnl Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
+# ceil.m4 serial 5
+dnl Copyright (C) 2007, 2009-2010 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_CEIL],
 [
+  m4_divert_text([DEFAULTS], [gl_ceil_required=plain])
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Test whether ceil() can be used without libm.
   gl_FUNC_CEIL_LIBS
   if test "$CEIL_LIBM" = "?"; then
     CEIL_LIBM=
   fi
+  m4_ifdef([gl_FUNC_CEIL_IEEE], [
+    if test $gl_ceil_required = ieee && test $REPLACE_CEIL = 0; then
+      AC_CACHE_CHECK([whether ceil works according to ISO C 99 with IEC 60559],
+        [gl_cv_func_ceil_ieee],
+        [
+          save_LIBS="$LIBS"
+          LIBS="$LIBS $CEIL_LIBM"
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_DOUBLE_MINUS_ZERO_CODE[
+]gl_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether ceil (-0.0) is -0.0.  */
+  if (signbitd (minus_zerod) && !signbitd (ceil (minus_zerod)))
+    return 1;
+  return 0;
+}
+            ]])],
+            [gl_cv_func_ceil_ieee=yes],
+            [gl_cv_func_ceil_ieee=no],
+            [gl_cv_func_ceil_ieee="guessing no"])
+          LIBS="$save_LIBS"
+        ])
+      case "$gl_cv_func_ceil_ieee" in
+        *yes) ;;
+        *) REPLACE_CEIL=1 ;;
+      esac
+    fi
+  ])
+  if test $REPLACE_CEIL = 1; then
+    AC_LIBOBJ([ceil])
+    CEIL_LIBM=
+  fi
   AC_SUBST([CEIL_LIBM])
 ])
 

--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 23
+# math_h.m4 serial 24
 dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -57,6 +57,7 @@
   GNULIB_ACOSL=0;    AC_SUBST([GNULIB_ACOSL])
   GNULIB_ASINL=0;    AC_SUBST([GNULIB_ASINL])
   GNULIB_ATANL=0;    AC_SUBST([GNULIB_ATANL])
+  GNULIB_CEIL=0;     AC_SUBST([GNULIB_CEIL])
   GNULIB_CEILF=0;    AC_SUBST([GNULIB_CEILF])
   GNULIB_CEILL=0;    AC_SUBST([GNULIB_CEILL])
   GNULIB_COSL=0;     AC_SUBST([GNULIB_COSL])
@@ -120,6 +121,7 @@
   HAVE_DECL_TRUNC=1;           AC_SUBST([HAVE_DECL_TRUNC])
   HAVE_DECL_TRUNCF=1;          AC_SUBST([HAVE_DECL_TRUNCF])
   HAVE_DECL_TRUNCL=1;          AC_SUBST([HAVE_DECL_TRUNCL])
+  REPLACE_CEIL=0;              AC_SUBST([REPLACE_CEIL])
   REPLACE_CEILF=0;             AC_SUBST([REPLACE_CEILF])
   REPLACE_CEILL=0;             AC_SUBST([REPLACE_CEILL])
   REPLACE_FLOOR=0;             AC_SUBST([REPLACE_FLOOR])

--- a/modules/ceil
+++ b/modules/ceil
@@ -2,13 +2,16 @@
 ceil() function: round towards positive infinity.
 
 Files:
+lib/ceil.c
 m4/ceil.m4
 
 Depends-on:
 math
+float
 
 configure.ac:
 gl_FUNC_CEIL
+gl_MATH_MODULE_INDICATOR([ceil])
 
 Makefile.am:
 

new file mode 100644
--- /dev/null
+++ b/modules/ceil-ieee
@@ -0,0 +1,27 @@
+Description:
+ceil() function according to ISO C 99 with IEC 60559.
+
+Files:
+m4/ceil-ieee.m4
+m4/minus-zero.m4
+m4/signbit.m4
+
+Depends-on:
+ceil
+
+configure.ac:
+gl_FUNC_CEIL_IEEE
+
+Makefile.am:
+
+Include:
+<math.h>
+
+Link:
+$(CEIL_LIBM)
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible

new file mode 100644
--- /dev/null
+++ b/modules/ceil-ieee-tests
@@ -0,0 +1,15 @@
+Files:
+tests/test-ceil-ieee.c
+tests/minus-zero.h
+tests/macros.h
+
+Depends-on:
+float
+signbit
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-ceil-ieee
+check_PROGRAMS += test-ceil-ieee
+test_ceil_ieee_LDADD = $(LDADD) @FLOOR_LIBM@

--- a/modules/math
+++ b/modules/math
@@ -29,6 +29,7 @@
 	      -e 's|@''GNULIB_ACOSL''@|$(GNULIB_ACOSL)|g' \
 	      -e 's|@''GNULIB_ASINL''@|$(GNULIB_ASINL)|g' \
 	      -e 's|@''GNULIB_ATANL''@|$(GNULIB_ATANL)|g' \
+	      -e 's|@''GNULIB_CEIL''@|$(GNULIB_CEIL)|g' \
 	      -e 's|@''GNULIB_CEILF''@|$(GNULIB_CEILF)|g' \
 	      -e 's|@''GNULIB_CEILL''@|$(GNULIB_CEILL)|g' \
 	      -e 's|@''GNULIB_COSL''@|$(GNULIB_COSL)|g' \
@@ -91,6 +92,7 @@
 	      -e 's|@''HAVE_DECL_TRUNC''@|$(HAVE_DECL_TRUNC)|g' \
 	      -e 's|@''HAVE_DECL_TRUNCF''@|$(HAVE_DECL_TRUNCF)|g' \
 	      -e 's|@''HAVE_DECL_TRUNCL''@|$(HAVE_DECL_TRUNCL)|g' \
+	      -e 's|@''REPLACE_CEIL''@|$(REPLACE_CEIL)|g' \
 	      -e 's|@''REPLACE_CEILF''@|$(REPLACE_CEILF)|g' \
 	      -e 's|@''REPLACE_CEILL''@|$(REPLACE_CEILL)|g' \
 	      -e 's|@''REPLACE_FLOOR''@|$(REPLACE_FLOOR)|g' \

new file mode 100644
--- /dev/null
+++ b/tests/test-ceil-ieee.c
@@ -0,0 +1,32 @@
+/* Test of rounding towards positive infinity.
+   Copyright (C) 2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <math.h>
+
+#include "minus-zero.h"
+#include "macros.h"
+
+int
+main ()
+{
+  /* Zero.  */
+  ASSERT (!signbit (ceil (0.0)));
+  ASSERT (!!signbit (ceil (minus_zerod)) == !!signbit (minus_zerod));
+
+  return 0;
+}

--- a/tests/test-math-c++.cc
+++ b/tests/test-math-c++.cc
@@ -80,6 +80,10 @@
 SIGNATURE_CHECK (GNULIB_NAMESPACE::ceilf, float, (float));
 #endif
 
+#if GNULIB_TEST_CEIL
+SIGNATURE_CHECK (GNULIB_NAMESPACE::ceil, double, (double));
+#endif
+
 #if GNULIB_TEST_CEILL
 SIGNATURE_CHECK (GNULIB_NAMESPACE::ceill, long double, (long double));
 #endif