diff --git a/Makefile b/Makefile
index 7dbd270..e00f42f 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ MODS = tjutil tjutf16 tjllist tjparserMonad tjjson \
        xmlm \
        cpdfwriteJSON cpdfstrftime cpdfcoord cpdf cpdfcommand
 
-SOURCES = $(foreach x,$(MODS),$(x).ml $(x).mli) cpdfcommandrun.ml
+SOURCES = gettimeofday.c $(foreach x,$(MODS),$(x).ml $(x).mli) cpdfcommandrun.ml
 
 RESULT = cpdf
 ANNOTATE = true
diff --git a/gettimeofday.c b/gettimeofday.c
new file mode 100644
index 0000000..7ce86f8
--- /dev/null
+++ b/gettimeofday.c
@@ -0,0 +1,27 @@
+/**************************************************************************/
+/*                                                                        */
+/*                                 OCaml                                  */
+/*                                                                        */
+/*             Xavier Leroy, projet Cristal, INRIA Rocquencourt           */
+/*                                                                        */
+/*   Copyright 1996 Institut National de Recherche en Informatique et     */
+/*     en Automatique.                                                    */
+/*                                                                        */
+/*   All rights reserved.  This file is distributed under the terms of    */
+/*   the GNU Lesser General Public License version 2.1, with the          */
+/*   special exception on linking described in the file LICENSE.          */
+/*                                                                        */
+/**************************************************************************/
+
+#include <caml/mlvalues.h>
+#include <caml/alloc.h>
+#include <caml/fail.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+CAMLprim value unix_gettimeofday(value unit)
+{
+  struct timeval tp;
+  gettimeofday(&tp, NULL);
+  return caml_copy_double((double) tp.tv_sec + (double) tp.tv_usec / 1e6);
+}