--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2009-12-11  Bruno Haible  <bruno@clisp.org>
+
+	New module 'langinfo'.
+	* lib/langinfo.in.h: New file.
+	* m4/langinfo_h.m4: New file.
+	* modules/langinfo: New file.
+	* doc/posix-headers/langinfo.texi: Mention the new module.
+
 2009-12-11  Bruno Haible  <bruno@clisp.org>
 
 	* lib/config.charset: Untabify.

--- a/doc/posix-headers/langinfo.texi
+++ b/doc/posix-headers/langinfo.texi
@@ -3,15 +3,22 @@
 
 POSIX specification: @url{http://www.opengroup.org/susv3xbd/langinfo.h.html}
 
-Gnulib module: ---
+Gnulib module: langinfo
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This header file is missing on some platforms:
+mingw, BeOS.
+@item
+The constant @code{CODESET} is not defined on some platforms:
+glibc 2.0.6, OpenBSD 3.8.
+@item
+The constants @code{ERA}, @code{ERA_D_FMT}, @code{ERA_D_T_FMT},
+@code{ERA_T_FMT}, @code{ALT_DIGITS} are not defined on some platforms:
+OpenBSD 3.8.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
-@item
-This header file is missing on some platforms:
-mingw, BeOS.
 @end itemize

new file mode 100644
--- /dev/null
+++ b/lib/langinfo.in.h
@@ -0,0 +1,161 @@
+/* Substitute for and wrapper around <langinfo.h>.
+   Copyright (C) 2009 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/*
+ * POSIX <langinfo.h> for platforms that lack it or have an incomplete one.
+ * <http://www.opengroup.org/onlinepubs/9699919799/basedefs/langinfo.h.html>
+ */
+
+#ifndef _GL_LANGINFO_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_LANGINFO_H@
+# @INCLUDE_NEXT@ @NEXT_LANGINFO_H@
+#endif
+
+#ifndef _GL_LANGINFO_H
+#define _GL_LANGINFO_H
+
+
+#if !@HAVE_LANGINFO_H@
+
+/* A platform that lacks <langinfo.h>.  */
+
+/* Assume that it also lacks <nl_types.h> and the nl_item type.  */
+typedef int nl_item;
+
+/* nl_langinfo items of the LC_CTYPE category */
+# define CODESET     10000
+/* nl_langinfo items of the LC_NUMERIC category */
+# define RADIXCHAR   10001
+# define THOUSEP     10002
+/* nl_langinfo items of the LC_TIME category */
+# define D_T_FMT     10003
+# define D_FMT       10004
+# define T_FMT       10005
+# define T_FMT_AMPM  10006
+# define AM_STR      10007
+# define PM_STR      10008
+# define DAY_1       10009
+# define DAY_2       (DAY_1 + 1)
+# define DAY_3       (DAY_1 + 2)
+# define DAY_4       (DAY_1 + 3)
+# define DAY_5       (DAY_1 + 4)
+# define DAY_6       (DAY_1 + 5)
+# define DAY_7       (DAY_1 + 6)
+# define ABDAY_1     10016
+# define ABDAY_2     (ABDAY_1 + 1)
+# define ABDAY_3     (ABDAY_1 + 2)
+# define ABDAY_4     (ABDAY_1 + 3)
+# define ABDAY_5     (ABDAY_1 + 4)
+# define ABDAY_6     (ABDAY_1 + 5)
+# define ABDAY_7     (ABDAY_1 + 6)
+# define MON_1       10023
+# define MON_2       (MON_1 + 1)
+# define MON_3       (MON_1 + 2)
+# define MON_4       (MON_1 + 3)
+# define MON_5       (MON_1 + 4)
+# define MON_6       (MON_1 + 5)
+# define MON_7       (MON_1 + 6)
+# define MON_8       (MON_1 + 7)
+# define MON_9       (MON_1 + 8)
+# define MON_10      (MON_1 + 9)
+# define MON_11      (MON_1 + 10)
+# define MON_12      (MON_1 + 11)
+# define ABMON_1     10035
+# define ABMON_2     (ABMON_1 + 1)
+# define ABMON_3     (ABMON_1 + 2)
+# define ABMON_4     (ABMON_1 + 3)
+# define ABMON_5     (ABMON_1 + 4)
+# define ABMON_6     (ABMON_1 + 5)
+# define ABMON_7     (ABMON_1 + 6)
+# define ABMON_8     (ABMON_1 + 7)
+# define ABMON_9     (ABMON_1 + 8)
+# define ABMON_10    (ABMON_1 + 9)
+# define ABMON_11    (ABMON_1 + 10)
+# define ABMON_12    (ABMON_1 + 11)
+# define ERA         10047
+# define ERA_D_FMT   10048
+# define ERA_D_T_FMT 10049
+# define ERA_T_FMT   10050
+# define ALT_DIGITS  10051
+/* nl_langinfo items of the LC_MONETARY category */
+# define CRNCYSTR    10052
+/* nl_langinfo items of the LC_MESSAGES category */
+# define YESEXPR     10053
+# define NOEXPR      10054
+
+#else
+
+/* A platform that has <langinfo.h>.  */
+
+# if !@HAVE_LANGINFO_CODESET@
+#  define CODESET     10000
+#  define GNULIB_defined_CODESET 1
+# endif
+
+# if !@HAVE_LANGINFO_ERA@
+#  define ERA         10047
+#  define ERA_D_FMT   10048
+#  define ERA_D_T_FMT 10049
+#  define ERA_T_FMT   10050
+#  define ALT_DIGITS  10051
+#  define GNULIB_defined_ERA 1
+# endif
+
+#endif
+
+
+/* Declare overridden functions.  */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* Return a piece of locale dependent information.
+   Note: The difference between nl_langinfo (CODESET) and locale_charset ()
+   is that the latter normalizes the encoding names to GNU conventions.  */
+
+#if @GNULIB_NL_LANGINFO@
+# if @REPLACE_NL_LANGINFO@
+#  undef nl_langinfo
+#  define nl_langinfo rpl_nl_langinfo
+# endif
+# if !@HAVE_NL_LANGINFO@ || @REPLACE_NL_LANGINFO@
+extern char *nl_langinfo (nl_item item);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef nl_langinfo
+# define nl_langinfo(i)                      \
+    (GL_LINK_WARNING ("nl_langinfo is not portable - " \
+                      "use gnulib module nl_langinfo for portability"), \
+     nl_langinfo (i))
+#endif
+
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* _GL_LANGINFO_H */
+#endif /* _GL_LANGINFO_H */

new file mode 100644
--- /dev/null
+++ b/m4/langinfo_h.m4
@@ -0,0 +1,76 @@
+# langinfo_h.m4 serial 1
+dnl Copyright (C) 2009 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_LANGINFO_H],
+[
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+
+  dnl Persuade glibc-2.0.6 <langinfo.h> to define CODESET.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  gl_CHECK_NEXT_HEADERS([langinfo.h])
+
+  dnl Determine whether <langinfo.h> exists. It is missing on mingw and BeOS.
+  HAVE_LANGINFO_CODESET=0
+  HAVE_LANGINFO_ERA=0
+  AC_CHECK_HEADERS_ONCE([langinfo.h])
+  if test $ac_cv_header_langinfo_h = yes; then
+    HAVE_LANGINFO_H=1
+    dnl Determine what <langinfo.h> defines. CODESET and ERA etc. are missing
+    dnl on OpenBSD 3.8.
+    AC_CACHE_CHECK([whether langinfo.h defines CODESET],
+      [gl_cv_header_langinfo_codeset],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = CODESET;
+]])],
+         [gl_cv_header_langinfo_codeset=yes],
+         [gl_cv_header_langinfo_codeset=no])
+      ])
+    if test $gl_cv_header_langinfo_codeset = yes; then
+      HAVE_LANGINFO_CODESET=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines ERA],
+      [gl_cv_header_langinfo_era],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ERA;
+]])],
+         [gl_cv_header_langinfo_era=yes],
+         [gl_cv_header_langinfo_era=no])
+      ])
+    if test $gl_cv_header_langinfo_era = yes; then
+      HAVE_LANGINFO_ERA=1
+    fi
+  else
+    HAVE_LANGINFO_H=0
+  fi
+  AC_SUBST([HAVE_LANGINFO_H])
+  AC_SUBST([HAVE_LANGINFO_CODESET])
+  AC_SUBST([HAVE_LANGINFO_ERA])
+
+  if test $HAVE_LANGINFO_H = 1 && test $HAVE_LANGINFO_CODESET = 1 && test $HAVE_LANGINFO_ERA = 1; then
+    LANGINFO_H=
+  else
+    LANGINFO_H='langinfo.h'
+  fi
+  AC_SUBST([LANGINFO_H])
+])
+
+AC_DEFUN([gl_LANGINFO_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  GNULIB_[]m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./-],[ABCDEFGHIJKLMNOPQRSTUVWXYZ___])=1
+])
+
+AC_DEFUN([gl_LANGINFO_H_DEFAULTS],
+[
+  GNULIB_NL_LANGINFO=0;  AC_SUBST([GNULIB_NL_LANGINFO])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_NL_LANGINFO=1;    AC_SUBST([HAVE_NL_LANGINFO])
+  REPLACE_NL_LANGINFO=0; AC_SUBST([REPLACE_NL_LANGINFO])
+])

new file mode 100644
--- /dev/null
+++ b/modules/langinfo
@@ -0,0 +1,44 @@
+Description:
+A GNU-like <langinfo.h>.
+
+Files:
+lib/langinfo.in.h
+m4/langinfo_h.m4
+
+Depends-on:
+include_next
+extensions
+
+configure.ac:
+gl_LANGINFO_H
+
+Makefile.am:
+BUILT_SOURCES += $(LANGINFO_H)
+
+# We need the following in order to create an empty placeholder for
+# <langinfo.h> when the system doesn't have one.
+langinfo.h: langinfo.in.h
+	$(AM_V_GEN)rm -f $@-t $@ && \
+	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+	  sed -e 's|@''HAVE_LANGINFO_H''@|$(HAVE_LANGINFO_H)|g' \
+	      -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+	      -e 's|@''NEXT_LANGINFO_H''@|$(NEXT_LANGINFO_H)|g' \
+	      -e 's|@''GNULIB_NL_LANGINFO''@|$(GNULIB_NL_LANGINFO)|g' \
+	      -e 's|@''HAVE_LANGINFO_CODESET''@|$(HAVE_LANGINFO_CODESET)|g' \
+	      -e 's|@''HAVE_LANGINFO_ERA''@|$(HAVE_LANGINFO_ERA)|g' \
+	      -e 's|@''HAVE_NL_LANGINFO''@|$(HAVE_NL_LANGINFO)|g' \
+	      -e 's|@''REPLACE_NL_LANGINFO''@|$(REPLACE_NL_LANGINFO)|g' \
+	      < $(srcdir)/langinfo.in.h; \
+	} > $@-t && \
+	mv $@-t $@
+MOSTLYCLEANFILES += langinfo.h langinfo.h-t
+
+Include:
+<langinfo.h>
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible