diff --git a/build-aux/configure-lib.sh b/build-aux/configure-lib.sh
index 71ac5a62..65cca4d5 100644
--- a/build-aux/configure-lib.sh
+++ b/build-aux/configure-lib.sh
@@ -321,6 +321,7 @@ lib/dirent/__getdirentries.c
 lib/dirent/closedir.c
 lib/dirent/opendir.c
 lib/dirent/readdir.c
+lib/locale/localeconv.c
 lib/math/ceil.c
 lib/math/fabs.c
 lib/math/floor.c
diff --git a/include/locale.h b/include/locale.h
index 44e58bdb..26a519f6 100644
--- a/include/locale.h
+++ b/include/locale.h
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2017,2018,2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -38,6 +38,30 @@
 #endif
 // *INDENT-ON*
 
+struct lconv
+{
+  char *decimal_point;
+  char *thousands_sep;
+  char *grouping;
+
+  char *int_curr_symbol;
+  char *currency_symbol;
+  char *mon_decimal_point;
+  char *mon_thousands_sep;
+  char *mon_grouping;
+  char *positive_sign;
+  char *negative_sign;
+  char int_frac_digits;
+  char frac_digits;
+  char p_cs_precedes;
+  char p_sep_by_space;
+  char n_cs_precedes;
+  char n_sep_by_space;
+  char p_sign_posn;
+  char n_sign_posn;
+};
+
+struct lconv * localeconv (void);
 char *setlocale (int category, char const *locale);
 
 #endif // ! SYSTEM_LIBC
diff --git a/lib/locale/localeconv.c b/lib/locale/localeconv.c
new file mode 100644
index 00000000..ebf76149
--- /dev/null
+++ b/lib/locale/localeconv.c
@@ -0,0 +1,51 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes 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.
+ *
+ * GNU Mes 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 GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <mes/lib.h>
+#include <locale.h>
+#include <limits.h>
+
+static struct lconv posix_lconv =
+  {
+    ".",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+    CHAR_MAX,
+  };
+
+struct lconv *
+localeconv (void)
+{
+  return (void *)&posix_lconv;
+}