--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-12-21  Bruno Haible  <bruno@clisp.org>
+
+	Work around a btowc() bug on IRIX 6.5.
+	* lib/wchar.in.h (btowc): Override if REPLACE_BTOWC is set.
+	* m4/btowc.m4 (gl_FUNC_BTOWC): Test whether btowc(EOF) is correct. Set
+	REPLACE_WTOBC if not.
+	* m4/wchar.m4 (gl_WCHAR_H_DEFAULTS): Initialize REPLACE_BTOWC.
+	* modules/wchar (Makefile.am): Substitute REPLACE_BTOWC.
+	* doc/posix-functions/btowc.texi: Mention the IRIX bug.
+
 2008-12-21  Bruno Haible  <bruno@clisp.org>
 
 	* modules/wcrtomb-tests: New file.

--- a/doc/posix-functions/btowc.texi
+++ b/doc/posix-functions/btowc.texi
@@ -11,6 +11,9 @@
 @item
 This function is missing on some platforms:
 HP-UX 11.00, IRIX 5.3, Solaris 2.6, mingw, Interix 3.5.
+@item
+This function does not return WEOF for an EOF argument on some platforms:
+IRIX 6.5.
 @end itemize
 
 Portability problems not fixed by Gnulib:

--- a/lib/wchar.in.h
+++ b/lib/wchar.in.h
@@ -84,7 +84,11 @@
 
 /* Convert a single-byte character to a wide character.  */
 #if @GNULIB_BTOWC@
-# if !@HAVE_BTOWC@
+# if @REPLACE_BTOWC@
+#  undef btowc
+#  define btowc rpl_btowc
+# endif
+# if !@HAVE_BTOWC@ || @REPLACE_BTOWC@
 extern wint_t btowc (int c);
 # endif
 #elif defined GNULIB_POSIXCHECK

--- a/m4/btowc.m4
+++ b/m4/btowc.m4
@@ -1,4 +1,4 @@
-# btowc.m4 serial 2
+# btowc.m4 serial 3
 dnl Copyright (C) 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,51 @@
   AC_CHECK_FUNCS_ONCE([btowc])
   if test $ac_cv_func_btowc = no; then
     HAVE_BTOWC=0
+  else
+
+    dnl IRIX 6.5 btowc(EOF) is 0xFF, not WEOF.
+    AC_REQUIRE([AC_PROG_CC])
+    AC_REQUIRE([gt_LOCALE_FR])
+    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+    AC_CACHE_CHECK([whether btowc(EOF) is correct],
+      [gl_cv_func_btowc_eof],
+      [
+        dnl Initial guess, used when cross-compiling or when no suitable locale
+        dnl is present.
+changequote(,)dnl
+        case "$host_os" in
+                 # Guess no on IRIX.
+          irix*) gl_cv_func_btowc_eof="guessing no" ;;
+                 # Guess yes otherwise.
+          *)     gl_cv_func_btowc_eof="guessing yes" ;;
+        esac
+changequote([,])dnl
+        if test $LOCALE_FR != none; then
+          AC_TRY_RUN([
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      if (btowc (EOF) != WEOF)
+        return 1;
+    }
+  return 0;
+}],
+            [gl_cv_func_btowc_eof=yes],
+            [gl_cv_func_btowc_eof=no],
+            [])
+        fi
+      ])
+    case "$gl_cv_func_btowc_eof" in
+      *yes) ;;
+      *) REPLACE_BTOWC=1 ;;
+    esac
+  fi
+  if test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1; then
     gl_REPLACE_WCHAR_H
     AC_LIBOBJ([btowc])
     gl_PREREQ_BTOWC

--- a/m4/wchar.m4
+++ b/m4/wchar.m4
@@ -7,7 +7,7 @@
 
 dnl Written by Eric Blake.
 
-# wchar.m4 serial 17
+# wchar.m4 serial 18
 
 AC_DEFUN([gl_WCHAR_H],
 [
@@ -81,6 +81,7 @@
   HAVE_DECL_WCTOB=1;   AC_SUBST([HAVE_DECL_WCTOB])
   HAVE_DECL_WCWIDTH=1; AC_SUBST([HAVE_DECL_WCWIDTH])
   REPLACE_MBSTATE_T=0; AC_SUBST([REPLACE_MBSTATE_T])
+  REPLACE_BTOWC=0;     AC_SUBST([REPLACE_BTOWC])
   REPLACE_WCTOB=0;     AC_SUBST([REPLACE_WCTOB])
   REPLACE_MBSINIT=0;   AC_SUBST([REPLACE_MBSINIT])
   REPLACE_MBRTOWC=0;   AC_SUBST([REPLACE_MBRTOWC])

--- a/modules/wchar
+++ b/modules/wchar
@@ -45,6 +45,7 @@
 	      -e 's|@''HAVE_DECL_WCTOB''@|$(HAVE_DECL_WCTOB)|g' \
 	      -e 's|@''HAVE_DECL_WCWIDTH''@|$(HAVE_DECL_WCWIDTH)|g' \
 	      -e 's|@''REPLACE_MBSTATE_T''@|$(REPLACE_MBSTATE_T)|g' \
+	      -e 's|@''REPLACE_BTOWC''@|$(REPLACE_BTOWC)|g' \
 	      -e 's|@''REPLACE_WCTOB''@|$(REPLACE_WCTOB)|g' \
 	      -e 's|@''REPLACE_MBSINIT''@|$(REPLACE_MBSINIT)|g' \
 	      -e 's|@''REPLACE_MBRTOWC''@|$(REPLACE_MBRTOWC)|g' \