diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index d4e2be458..00d94efcc 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2014-08-04  Anthony Heading  <anthony@ajrh.net>
+
+	* include/sys/file.h: Add extern "C".
+
 2014-08-04  Corinna Vinschen  <corinna@vinschen.de>
 
 	* common.din (__cxa_atexit): Export.
diff --git a/winsup/cygwin/include/sys/file.h b/winsup/cygwin/include/sys/file.h
index 9b72ee9c2..6dabeb70c 100644
--- a/winsup/cygwin/include/sys/file.h
+++ b/winsup/cygwin/include/sys/file.h
@@ -39,8 +39,17 @@
 #define LOCK_NB		0x04		/* don't block when locking */
 #define LOCK_UN		0x08		/* unlock file */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 extern int flock _PARAMS ((int, int));
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
 
 #endif