--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2011-02-06  Bruno Haible  <bruno@clisp.org>
+
+	New module 'wctrans'.
+	* modules/wctrans: New file.
+	* lib/wctype.in.h (wctrans): New declaration.
+	* lib/wctrans.c: New file.
+	* lib/wctrans-impl.h: New file.
+	* m4/wctrans.m4: New file.
+	* m4/wctype_h.m4 (gl_WCTYPE_H): Test whether wctrans is declared.
+	(gl_WCTYPE_H_DEFAULTS): Initialize GNULIB_WCTRANS.
+	* modules/wctype-h (Makefile.am): Substitute GNULIB_WCTRANS.
+	* tests/test-wctype-h-c++.cc: Test the declaration of wctrans.
+	* doc/posix-functions/wctrans.texi: Mention the new module.
+
 2011-02-06  Bruno Haible  <bruno@clisp.org>
 
 	New module 'iswctype'.

--- a/doc/posix-functions/wctrans.texi
+++ b/doc/posix-functions/wctrans.texi
@@ -4,18 +4,18 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/wctrans.html}
 
-Gnulib module: ---
+Gnulib module: wctrans
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function is missing on some platforms:
+HP-UX 11.00, IRIX 6.5, Solaris 2.5.1, mingw, Interix 3.5.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
 @item
-This function is missing on some platforms:
-HP-UX 11.00, IRIX 6.5, Solaris 2.5.1, mingw, Interix 3.5.
-@item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
 @end itemize

new file mode 100644
--- /dev/null
+++ b/lib/wctrans-impl.h
@@ -0,0 +1,37 @@
+/* Get descriptor for a wide character case conversion.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2011.
+
+   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/>.  */
+
+wctrans_t
+wctrans (const char *name)
+{
+  if (name[0] == 't'
+      && name[1] == 'o')
+    switch (name[2])
+      {
+      case 'l':
+        if (strcmp (name + 3, "ower") == 0)
+          return (wctrans_t) towlower;
+        break;
+      case 'u':
+        if (strcmp (name + 3, "pper") == 0)
+          return (wctrans_t) towupper;
+        break;
+      default:
+        break;
+      }
+  return NULL;
+}

new file mode 100644
--- /dev/null
+++ b/lib/wctrans.c
@@ -0,0 +1,25 @@
+/* Get descriptor for a wide character case conversion.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2011.
+
+   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>
+
+/* Specification.  */
+#include <wctype.h>
+
+#include <string.h>
+
+#include "wctrans-impl.h"

--- a/lib/wctype.in.h
+++ b/lib/wctype.in.h
@@ -433,6 +433,21 @@
 # endif
 #endif
 
+/* Get a descriptor for a wide character case conversion.  */
+#if @GNULIB_WCTRANS@
+# if !@HAVE_WCTRANS_T@
+_GL_FUNCDECL_SYS (wctrans, wctrans_t, (const char *name));
+# endif
+_GL_CXXALIAS_SYS (wctrans, wctrans_t, (const char *name));
+_GL_CXXALIASWARN (wctrans);
+#elif defined GNULIB_POSIXCHECK
+# undef wctrans
+# if HAVE_RAW_DECL_WCTRANS
+_GL_WARN_ON_USE (wctrans, "wctrans is unportable - "
+                 "use gnulib module wctrans for portability");
+# endif
+#endif
+
 
 #endif /* _GL_WCTYPE_H */
 #endif /* _GL_WCTYPE_H */

new file mode 100644
--- /dev/null
+++ b/m4/wctrans.m4
@@ -0,0 +1,14 @@
+# wctrans.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_WCTRANS],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([gl_WCTYPE_H])
+  if test $HAVE_WCTRANS_T = 0; then
+    AC_LIBOBJ([wctrans])
+  fi
+])

--- a/m4/wctype_h.m4
+++ b/m4/wctype_h.m4
@@ -146,7 +146,7 @@
 #endif
 #include <wctype.h>
     ]],
-    [wctype iswctype
+    [wctype iswctype wctrans
     ])
 ])
 
@@ -164,6 +164,7 @@
   GNULIB_ISWBLANK=0;    AC_SUBST([GNULIB_ISWBLANK])
   GNULIB_WCTYPE=0;      AC_SUBST([GNULIB_WCTYPE])
   GNULIB_ISWCTYPE=0;    AC_SUBST([GNULIB_ISWCTYPE])
+  GNULIB_WCTRANS=0;     AC_SUBST([GNULIB_WCTRANS])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_ISWBLANK=1;      AC_SUBST([HAVE_ISWBLANK])
   HAVE_WCTYPE_T=1;      AC_SUBST([HAVE_WCTYPE_T])

new file mode 100644
--- /dev/null
+++ b/modules/wctrans
@@ -0,0 +1,25 @@
+Description:
+wctrans() function: get descriptor for a wide character case conversion.
+
+Files:
+lib/wctrans.c
+lib/wctrans-impl.h
+m4/wctrans.m4
+
+Depends-on:
+wctype-h
+
+configure.ac:
+gl_FUNC_WCTRANS
+gl_WCTYPE_MODULE_INDICATOR([wctrans])
+
+Makefile.am:
+
+Include:
+<wctype.h>
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible

--- a/modules/wctype-h
+++ b/modules/wctype-h
@@ -30,6 +30,7 @@
 	      -e 's/@''GNULIB_ISWBLANK''@/$(GNULIB_ISWBLANK)/g' \
 	      -e 's/@''GNULIB_WCTYPE''@/$(GNULIB_WCTYPE)/g' \
 	      -e 's/@''GNULIB_ISWCTYPE''@/$(GNULIB_ISWCTYPE)/g' \
+	      -e 's/@''GNULIB_WCTRANS''@/$(GNULIB_WCTRANS)/g' \
 	      -e 's/@''HAVE_ISWBLANK''@/$(HAVE_ISWBLANK)/g' \
 	      -e 's/@''HAVE_ISWCNTRL''@/$(HAVE_ISWCNTRL)/g' \
 	      -e 's/@''HAVE_WCTYPE_T''@/$(HAVE_WCTYPE_T)/g' \

--- a/tests/test-wctype-h-c++.cc
+++ b/tests/test-wctype-h-c++.cc
@@ -50,6 +50,10 @@
 SIGNATURE_CHECK (GNULIB_NAMESPACE::towlower, wint_t, (wint_t));
 SIGNATURE_CHECK (GNULIB_NAMESPACE::towupper, wint_t, (wint_t));
 
+#if GNULIB_TEST_WCTRANS
+SIGNATURE_CHECK (GNULIB_NAMESPACE::wctrans, wctrans_t, (const char *));
+#endif
+
 
 int
 main ()