diff --git a/include/libmes.h b/include/libmes.h
index 01bdf70f..f13d1f84 100644
--- a/include/libmes.h
+++ b/include/libmes.h
@@ -21,11 +21,35 @@
 #ifndef __MES_LIBMES_H
 #define __MES_LIBMES_H
 
+#ifndef _SIZE_T
+#define _SIZE_T
+#ifndef __SIZE_T
+#define __SIZE_T
+#ifndef __MES_SIZE_T
+#define __MES_SIZE_T
+#undef size_t
+typedef unsigned long size_t;
+#endif
+#endif
+#endif
+
+#ifndef _SSIZE_T
+#define _SSIZE_T
+#ifndef __SSIZE_T
+#define __SSIZE_T
+#ifndef __MES_SSIZE_T
+#define __MES_SSIZE_T
+#undef ssize_t
+typedef long ssize_t;
+#endif
+#endif
+#endif
+
 int __mes_debug ();
-char const* number_to_ascii (int number, int base, int signed_p);
-char const* itoa (int number);
-char const* utoa (unsigned number);
-char const* itoab (int x, int base);
+char const* number_to_ascii (long number, int base, int signed_p);
+char const* itoa (long number);
+char const* utoa (unsigned long number);
+char const* itoab (long x, int base);
 int _atoi (char const**, int base);
 int atoi (char const *s);
 int eputc (int c);
@@ -38,5 +62,6 @@ int isdigit (int c);
 int isspace (int c);
 int isxdigit (int c);
 int oputs (char const* s);
+ssize_t write (int filedes, void const *buffer, size_t size);
 
 #endif //__MES_LIBMES_H
diff --git a/lib/libc-mini.c b/lib/libc-mini.c
index b4aa79f9..cbf543ca 100644
--- a/lib/libc-mini.c
+++ b/lib/libc-mini.c
@@ -18,64 +18,10 @@
  * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <errno.h>
-
-#ifndef _SIZE_T
-#define _SIZE_T
-#ifndef __SIZE_T
-#define __SIZE_T
-#ifndef __MES_SIZE_T
-#define __MES_SIZE_T
-#undef size_t
-typedef unsigned long size_t;
-#endif
-#endif
-#endif
-
-#ifndef _SSIZE_T
-#define _SSIZE_T
-#ifndef __SSIZE_T
-#define __SSIZE_T
-#ifndef __MES_SSIZE_T
-#define __MES_SSIZE_T
-#undef ssize_t
-typedef long ssize_t;
-#endif
-#endif
-#endif
-
-ssize_t write (int filedes, void const *buffer, size_t size);
-
-size_t
-strlen (char const* s)
-{
-  int i = 0;
-  while (s[i]) i++;
-  return i;
-}
-
-int
-eputs (char const* s)
-{
-  int i = strlen (s);
-  write (2, s, i);
-  return 0;
-}
-
-int
-oputs (char const* s)
-{
-  int i = strlen (s);
-  write (1, s, i);
-  return 0;
-}
-
-int
-puts (char const* s)
-{
-  oputs (s);
-  return oputs ("\n");
-}
+#include <string/strlen.c>
+#include <mes/eputs.c>
+#include <mes/oputs.c>
+#include <stdlib/puts.c>
 
 #if __GNU__
 #include <hurd/libc-mini.c>
@@ -85,12 +31,4 @@ puts (char const* s)
 #error both __GNU__ and _linux__ are undefined, choose one
 #endif
 
-void (*__call_at_exit) (void);
-
-void
-exit (int code)
-{
-  if (__call_at_exit)
-    (*__call_at_exit) ();
-  _exit (code);
-}
+#include <stdlib/exit.c>
diff --git a/lib/mes/eputs.c b/lib/mes/eputs.c
new file mode 100644
index 00000000..a22b145d
--- /dev/null
+++ b/lib/mes/eputs.c
@@ -0,0 +1,29 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018 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 <libmes.h>
+
+int
+eputs (char const* s)
+{
+  int i = strlen (s);
+  write (2, s, i);
+  return 0;
+}
diff --git a/lib/mes/oputs.c b/lib/mes/oputs.c
new file mode 100644
index 00000000..123a8117
--- /dev/null
+++ b/lib/mes/oputs.c
@@ -0,0 +1,29 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018 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 <libmes.h>
+
+int
+oputs (char const* s)
+{
+  int i = strlen (s);
+  write (1, s, i);
+  return 0;
+}
diff --git a/lib/stdlib/exit.c b/lib/stdlib/exit.c
new file mode 100644
index 00000000..29be6d12
--- /dev/null
+++ b/lib/stdlib/exit.c
@@ -0,0 +1,31 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018 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 <libmes.h>
+
+void (*__call_at_exit) (void);
+
+void
+exit (int code)
+{
+  if (__call_at_exit)
+    (*__call_at_exit) ();
+  _exit (code);
+}
diff --git a/lib/stdlib/puts.c b/lib/stdlib/puts.c
new file mode 100644
index 00000000..be51f47b
--- /dev/null
+++ b/lib/stdlib/puts.c
@@ -0,0 +1,28 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018 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 <libmes.h>
+
+int
+puts (char const* s)
+{
+  oputs (s);
+  return oputs ("\n");
+}
diff --git a/lib/string/strlen.c b/lib/string/strlen.c
new file mode 100644
index 00000000..0f6df8ad
--- /dev/null
+++ b/lib/string/strlen.c
@@ -0,0 +1,30 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018 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 <libmes.h>
+
+size_t
+strlen (char const* s)
+{
+  int i = 0;
+  while (s[i])
+    i++;
+  return i;
+}