--- a/ChangeLog	Sat Sep 23 09:26:48 2017 +0200
+++ b/ChangeLog	Sat Sep 23 12:22:17 2017 +0200
@@ -1,5 +1,13 @@
 2017-09-23  Bruno Haible  <bruno@clisp.org>
 
+	strfmon_l: New module.
+	* modules/strfmon_l: New file.
+	* lib/strfmon_l.c: New file.
+	* m4/strfmon_l.m4: New file.
+	* doc/posix-functions/strfmon_l.texi: Mention the new module.
+	* modules/strfmon_l-tests: New file.
+	* tests/test-strfmon_l.c: New file.
+
 	monetary: New module.
 	* modules/monetary: New file.
 	* lib/monetary.in.h: New file.

--- a/doc/posix-functions/strfmon_l.texi	Sat Sep 23 09:26:48 2017 +0200
+++ b/doc/posix-functions/strfmon_l.texi	Sat Sep 23 12:22:17 2017 +0200
@@ -4,10 +4,13 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/strfmon_l.html}
 
-Gnulib module: ---
+Gnulib module: strfmon_l
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function uses a wrong locale for the numbers on some platforms:
+glibc 2.23.
 @end itemize
 
 Portability problems not fixed by Gnulib:

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/strfmon_l.c	Sat Sep 23 12:22:17 2017 +0200
@@ -0,0 +1,64 @@
+/* strfmon_l override.
+   Copyright (C) 2017 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, 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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <monetary.h>
+
+#include <locale.h>
+#include <stdarg.h>
+
+#undef strfmon_l
+
+/* This override can only support a limited number of arguments.  */
+#define MAX_ARG_WORDS 16
+
+ssize_t
+rpl_strfmon_l (char *s, size_t maxsize, locale_t locale, const char *format, ...)
+{
+  /* Work around glibc 2.23 bug
+     <https://sourceware.org/bugzilla/show_bug.cgi?id=19633>.  */
+  va_list argptr;
+  double args[MAX_ARG_WORDS];
+  int i;
+  locale_t orig_locale;
+  ssize_t result;
+
+  orig_locale = uselocale ((locale_t)0);
+
+  if (uselocale (locale) == (locale_t)0)
+    /* errno is set.  */
+    return -1;
+
+  va_start (argptr, format);
+  /* Hack: Consume more arguments than those that are actually given.  */
+  for (i = 0; i < MAX_ARG_WORDS; i++)
+    args[i] = va_arg (argptr, double);
+
+  result = strfmon_l (s, maxsize, locale, format,
+                      args[0], args[1], args[2], args[3], args[4], args[5],
+                      args[6], args[7], args[8], args[9], args[10], args[11],
+                      args[12], args[13], args[14], args[15]);
+
+  va_end (argptr);
+
+  if (uselocale (orig_locale) == (locale_t)0)
+    /* errno is set.  */
+    return -1;
+
+  return result;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m4/strfmon_l.m4	Sat Sep 23 12:22:17 2017 +0200
@@ -0,0 +1,46 @@
+# strfmon_l.m4 serial 1
+dnl Copyright (C) 2017 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_STRFMON_L],
+[
+  AC_REQUIRE([gl_MONETARY_H_DEFAULTS])
+
+  dnl Persuade glibc <monetary.h> to declare strfmon_l().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  dnl On Mac OS X 10.12, <monetary.h> may declare strfmon_l() if
+  dnl _USE_EXTENDED_LOCALES_ is defined. But this symbol is supposed
+  dnl to be defined by <xlocale.h>, not by us.
+
+  AC_CHECK_FUNCS_ONCE([strfmon_l])
+  if test $ac_cv_func_strfmon_l = yes; then
+    dnl Test for bug <https://sourceware.org/bugzilla/show_bug.cgi?id=19633>
+    dnl which was fixed in glibc-2.24.
+    AC_CACHE_CHECK([whether strfmon_l works],
+      [gl_cv_strfmon_l_works],
+      [AC_EGREP_CPP([Unlucky],
+         [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ < 24)
+  Unlucky GNU user
+ #endif
+#endif
+         ],
+         [gl_cv_strfmon_l_works=no],
+         [gl_cv_strfmon_l_works="guessing yes"])
+      ])
+    if test "$gl_cv_strfmon_l_works" = no; then
+      REPLACE_STRFMON_L=1
+    fi
+  else
+    HAVE_STRFMON_L=0
+  fi
+])
+
+# Prerequisites of lib/strfmon_l.c.
+AC_DEFUN([gl_PREREQ_STRFMON_L], [
+  :
+])

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/strfmon_l	Sat Sep 23 12:22:17 2017 +0200
@@ -0,0 +1,31 @@
+Description:
+strfmon_l() function: formatted conversion of monetary value to string.
+
+Files:
+lib/strfmon_l.c
+m4/strfmon_l.m4
+
+Depends-on:
+monetary
+extensions
+
+configure.ac:
+gl_FUNC_STRFMON_L
+if test $REPLACE_STRFMON_L = 1; then
+  AC_LIBOBJ([strfmon_l])
+  gl_PREREQ_STRFMON_L
+fi
+gl_MONETARY_MODULE_INDICATOR([strfmon_l])
+
+Makefile.am:
+
+Include:
+#if HAVE_MONETARY_H
+<monetary.h>
+#endif
+
+License:
+LGPLv2+
+
+Maintainer:
+all

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/strfmon_l-tests	Sat Sep 23 12:22:17 2017 +0200
@@ -0,0 +1,12 @@
+Files:
+tests/test-strfmon_l.c
+tests/signature.h
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-strfmon_l
+check_PROGRAMS += test-strfmon_l

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-strfmon_l.c	Sat Sep 23 12:22:17 2017 +0200
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2017 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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#if HAVE_MONETARY_H
+# include <monetary.h>
+#endif
+
+#include "signature.h"
+#if HAVE_STRFMON_L
+SIGNATURE_CHECK (strfmon_l, ssize_t, (char *s, size_t maxsize, locale_t locale,
+                                      const char *format, ...));
+#endif
+
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "macros.h"
+
+int
+main (void)
+{
+#if HAVE_STRFMON_L
+  /* Simple test in the C locale.  */
+  {
+    char buf[80];
+    locale_t loc;
+    ssize_t ret;
+
+    loc = newlocale (LC_ALL_MASK, "C", NULL);
+    ASSERT (loc != NULL);
+    ret = strfmon_l (buf, sizeof (buf), loc, "%^#5.0n", 123.4);
+    ASSERT (   (ret == 5 && strcmp (buf,  "  123") == 0) /* AIX, Solaris */
+            || (ret == 6 && strcmp (buf, "   123") == 0) /* glibc */
+            || (ret == 7 && strcmp (buf, "   123 ") == 0) /* Mac OS X */
+           );
+  }
+
+  /* Test whether the decimal point comes from the right locale:
+     glibc bug <https://sourceware.org/bugzilla/show_bug.cgi?id=19633>.  */
+  if (setlocale (LC_ALL, "en_US.UTF-8") == NULL)
+    {
+      fprintf (stderr, "Skipping test: English Unicode locale is not installed\n");
+      return 77;
+    }
+  if (setlocale (LC_ALL, "de_DE.UTF-8") == NULL)
+    {
+      fprintf (stderr, "Skipping test: English Unicode locale is not installed\n");
+      return 77;
+    }
+  {
+    char expected_buf[80];
+    locale_t loc;
+    char buf[80];
+
+    setlocale (LC_ALL, "en_US.UTF-8");
+    ASSERT (strfmon (expected_buf, sizeof (expected_buf), "%.2n", 123.5) >= 0);
+    setlocale (LC_ALL, "de_DE.UTF-8");
+    loc = newlocale (LC_ALL_MASK, "en_US.UTF-8", NULL);
+    ASSERT (strfmon_l (buf, sizeof (buf), loc, "%.2n", 123.5) >= 0);
+    ASSERT (strcmp (buf, expected_buf) == 0);
+  }
+  {
+    char expected_buf[80];
+    locale_t loc;
+    char buf[80];
+
+    setlocale (LC_ALL, "de_DE.UTF-8");
+    ASSERT (strfmon (expected_buf, sizeof (expected_buf), "%.2n", 123.5) >= 0);
+    setlocale (LC_ALL, "en_US.UTF-8");
+    loc = newlocale (LC_ALL_MASK, "de_DE.UTF-8", NULL);
+    ASSERT (strfmon_l (buf, sizeof (buf), loc, "%.2n", 123.5) >= 0);
+    ASSERT (strcmp (buf, expected_buf) == 0);
+  }
+#endif
+
+  return 0;
+}