--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2011-02-06  Bruno Haible  <bruno@clisp.org>
+
+	New module 'iswblank'.
+	* lib/wctype.in.h (iswblank): Don't declare if GNULIB_ISWBLANK is 0.
+	* modules/iswblank: New file.
+	* modules/wctype-h (Files): Remove lib/iswblank.c.
+	(Makefile.am): Substitute GNULIB_ISWBLANK.
+	* m4/iswblank.m4: New file, partially extracted from m4/wctype_h.m4.
+	* m4/wctype_h.m4 (gl_WCTYPE_MODULE_INDICATOR): New macro.
+	(gl_WCTYPE_H_DEFAULTS): New macro.
+	(gl_WCTYPE_H): Require it. Remove iswblank related code.
+	* modules/iswblank-tests: New file.
+	* tests/test-iswblank.c: New file, extraced from tests/test-wctype-h.c.
+	* tests/test-wctype-h.c (main): Remove iswblank tests.
+	* tests/test-wctype-h-c++.cc: Guard the signature test of iswblank.
+	* doc/posix-functions/iswblank.texi: Mention module 'iswblank' instead
+	of 'wctype-h'.
+	* NEWS: Mention the change.
+	* modules/mbchar (Depends-on): Add iswblank.
+
 2011-02-08  Bruno Haible  <bruno@clisp.org>
 
 	di-set tests: Refactor.

--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,10 @@
 
 Date        Modules         Changes
 
+2011-02-08  wctype-h        This module no longer provides the iswblank()
+                            function. If you need this function, you now need
+                            to request the 'iswblank' module.
+
 2011-02-07  wctype          This module is renamed to wctype-h.
 
 2011-01-18  multiarch       This no longer #defines AA_APPLE_UNIVERSAL_BUILD;

--- a/doc/posix-functions/iswblank.texi
+++ b/doc/posix-functions/iswblank.texi
@@ -4,7 +4,7 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/iswblank.html}
 
-Gnulib module: wctype-h
+Gnulib module: iswblank
 
 Portability problems fixed by Gnulib:
 @itemize

--- a/lib/wctype.in.h
+++ b/lib/wctype.in.h
@@ -279,7 +279,7 @@
   return (wc >= 'a' && wc <= 'z' ? wc - 'a' + 'A' : wc);
 }
 
-# elif ! @HAVE_ISWBLANK@ || @REPLACE_ISWBLANK@
+# elif @GNULIB_ISWBLANK@ && (! @HAVE_ISWBLANK@ || @REPLACE_ISWBLANK@)
 /* Only the iswblank function is missing.  */
 
 #  if @REPLACE_ISWBLANK@
@@ -334,7 +334,6 @@
 #if @REPLACE_ISWCNTRL@
 _GL_CXXALIAS_RPL (iswalnum, int, (wint_t wc));
 _GL_CXXALIAS_RPL (iswalpha, int, (wint_t wc));
-_GL_CXXALIAS_RPL (iswblank, int, (wint_t wc));
 _GL_CXXALIAS_RPL (iswcntrl, int, (wint_t wc));
 _GL_CXXALIAS_RPL (iswdigit, int, (wint_t wc));
 _GL_CXXALIAS_RPL (iswgraph, int, (wint_t wc));
@@ -347,11 +346,6 @@
 #else
 _GL_CXXALIAS_SYS (iswalnum, int, (wint_t wc));
 _GL_CXXALIAS_SYS (iswalpha, int, (wint_t wc));
-# if @REPLACE_ISWBLANK@
-_GL_CXXALIAS_RPL (iswblank, int, (wint_t wc));
-# else
-_GL_CXXALIAS_SYS (iswblank, int, (wint_t wc));
-# endif
 _GL_CXXALIAS_SYS (iswcntrl, int, (wint_t wc));
 _GL_CXXALIAS_SYS (iswdigit, int, (wint_t wc));
 _GL_CXXALIAS_SYS (iswgraph, int, (wint_t wc));
@@ -364,7 +358,6 @@
 #endif
 _GL_CXXALIASWARN (iswalnum);
 _GL_CXXALIASWARN (iswalpha);
-_GL_CXXALIASWARN (iswblank);
 _GL_CXXALIASWARN (iswcntrl);
 _GL_CXXALIASWARN (iswdigit);
 _GL_CXXALIASWARN (iswgraph);
@@ -375,6 +368,15 @@
 _GL_CXXALIASWARN (iswupper);
 _GL_CXXALIASWARN (iswxdigit);
 
+#if @GNULIB_ISWBLANK@
+# if @REPLACE_ISWCNTRL@ || @REPLACE_ISWBLANK@
+_GL_CXXALIAS_RPL (iswblank, int, (wint_t wc));
+# else
+_GL_CXXALIAS_SYS (iswblank, int, (wint_t wc));
+# endif
+_GL_CXXALIASWARN (iswblank);
+#endif
+
 #if @REPLACE_ISWCNTRL@ || defined __MINGW32__
 _GL_CXXALIAS_RPL (towlower, wint_t, (wint_t wc));
 _GL_CXXALIAS_RPL (towupper, wint_t, (wint_t wc));

new file mode 100644
--- /dev/null
+++ b/m4/iswblank.m4
@@ -0,0 +1,29 @@
+# iswblank.m4 serial 1
+dnl Copyright (C) 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_ISWBLANK],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H])
+  AC_CHECK_FUNCS_ONCE([iswblank])
+  AC_CHECK_DECLS_ONCE([iswblank])
+  if test $ac_cv_func_iswblank = no; then
+    HAVE_ISWBLANK=0
+    if test $ac_cv_have_decl_iswblank = yes; then
+      REPLACE_ISWBLANK=1
+    fi
+  fi
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl Redefine all of iswcntrl, ..., towupper in <wctype.h>.
+    :
+  else
+    if test $HAVE_ISWBLANK = 0 || test $REPLACE_ISWBLANK = 1; then
+      dnl Redefine only iswblank.
+      AC_LIBOBJ([iswblank])
+    fi
+  fi
+
+])

--- a/m4/wctype_h.m4
+++ b/m4/wctype_h.m4
@@ -1,4 +1,4 @@
-# wctype_h.m4 serial 12
+# wctype_h.m4 serial 13
 
 dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
 
@@ -11,6 +11,7 @@
 
 AC_DEFUN([gl_WCTYPE_H],
 [
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_CHECK_FUNCS_ONCE([iswcntrl])
@@ -20,21 +21,6 @@
     HAVE_ISWCNTRL=0
   fi
   AC_SUBST([HAVE_ISWCNTRL])
-  AC_CHECK_FUNCS_ONCE([iswblank])
-  AC_CHECK_DECLS_ONCE([iswblank])
-  if test $ac_cv_func_iswblank = yes; then
-    HAVE_ISWBLANK=1
-    REPLACE_ISWBLANK=0
-  else
-    HAVE_ISWBLANK=0
-    if test $ac_cv_have_decl_iswblank = yes; then
-      REPLACE_ISWBLANK=1
-    else
-      REPLACE_ISWBLANK=0
-    fi
-  fi
-  AC_SUBST([HAVE_ISWBLANK])
-  AC_SUBST([REPLACE_ISWBLANK])
 
   AC_REQUIRE([AC_C_INLINE])
 
@@ -91,10 +77,22 @@
   if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
     dnl Redefine all of iswcntrl, ..., towupper in <wctype.h>.
     :
-  else
-    if test $HAVE_ISWBLANK = 0 || test $REPLACE_ISWBLANK = 1; then
-      dnl Redefine only iswblank.
-      AC_LIBOBJ([iswblank])
-    fi
   fi
 ])
+
+AC_DEFUN([gl_WCTYPE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_WCTYPE_H_DEFAULTS],
+[
+  GNULIB_ISWBLANK=0;    AC_SUBST([GNULIB_ISWBLANK])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_ISWBLANK=1;      AC_SUBST([HAVE_ISWBLANK])
+  REPLACE_ISWBLANK=0;   AC_SUBST([REPLACE_ISWBLANK])
+])

new file mode 100644
--- /dev/null
+++ b/modules/iswblank
@@ -0,0 +1,24 @@
+Description:
+iswblank() function: test wide character for being blank.
+
+Files:
+lib/iswblank.c
+m4/iswblank.m4
+
+Depends-on:
+wctype-h
+
+configure.ac:
+gl_FUNC_ISWBLANK
+gl_WCTYPE_MODULE_INDICATOR([iswblank])
+
+Makefile.am:
+
+Include:
+<wctype.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Bruno Haible

new file mode 100644
--- /dev/null
+++ b/modules/iswblank-tests
@@ -0,0 +1,12 @@
+Files:
+tests/test-iswblank.c
+tests/macros.h
+
+Depends-on:
+wctype-h-c++-tests
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-iswblank
+check_PROGRAMS += test-iswblank

--- a/modules/mbchar
+++ b/modules/mbchar
@@ -11,6 +11,7 @@
 stdbool
 wchar
 wctype-h
+iswblank
 wcwidth
 memcmp
 

--- a/modules/wctype-h
+++ b/modules/wctype-h
@@ -3,7 +3,6 @@
 
 Files:
 lib/wctype.in.h
-lib/iswblank.c
 m4/wctype_h.m4
 m4/wint_t.m4
 
@@ -28,6 +27,7 @@
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_WCTYPE_H''@|$(NEXT_WCTYPE_H)|g' \
+	      -e 's/@''GNULIB_ISWBLANK''@/$(GNULIB_ISWBLANK)/g' \
 	      -e 's/@''HAVE_ISWBLANK''@/$(HAVE_ISWBLANK)/g' \
 	      -e 's/@''HAVE_ISWCNTRL''@/$(HAVE_ISWCNTRL)/g' \
 	      -e 's/@''HAVE_WINT_T''@/$(HAVE_WINT_T)/g' \

new file mode 100644
--- /dev/null
+++ b/tests/test-iswblank.c
@@ -0,0 +1,35 @@
+/* Test of iswblank() function.
+   Copyright (C) 2007-2011 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 <wctype.h>
+
+#include "macros.h"
+
+/* Check that WEOF is defined.  */
+wint_t e = WEOF;
+
+int
+main (void)
+{
+  /* Check that the function exist as a function or as a macro.  */
+  (void) iswblank (0);
+  /* Check that the isw* functions map WEOF to 0.  */
+  ASSERT (!iswblank (e));
+
+  return 0;
+}

--- a/tests/test-wctype-h-c++.cc
+++ b/tests/test-wctype-h-c++.cc
@@ -26,7 +26,9 @@
 
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswalnum, int, (wint_t));
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswalpha, int, (wint_t));
+#if GNULIB_TEST_ISWBLANK
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswblank, int, (wint_t));
+#endif
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswcntrl, int, (wint_t));
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswdigit, int, (wint_t));
 SIGNATURE_CHECK (GNULIB_NAMESPACE::iswgraph, int, (wint_t));

--- a/tests/test-wctype-h.c
+++ b/tests/test-wctype-h.c
@@ -33,7 +33,6 @@
   /* Check that the isw* functions exist as functions or as macros.  */
   (void) iswalnum (0);
   (void) iswalpha (0);
-  (void) iswblank (0);
   (void) iswcntrl (0);
   (void) iswdigit (0);
   (void) iswgraph (0);
@@ -47,7 +46,6 @@
   /* Check that the isw* functions map WEOF to 0.  */
   ASSERT (!iswalnum (e));
   ASSERT (!iswalpha (e));
-  ASSERT (!iswblank (e));
   ASSERT (!iswcntrl (e));
   ASSERT (!iswdigit (e));
   ASSERT (!iswgraph (e));