diff --git a/src/libCom/osi/os/vxWorks/osdSock.h b/src/libCom/osi/os/vxWorks/osdSock.h
index 8b1171f28..d632f361f 100644
--- a/src/libCom/osi/os/vxWorks/osdSock.h
+++ b/src/libCom/osi/os/vxWorks/osdSock.h
@@ -24,6 +24,8 @@ extern "C" {
 #include <ioLib.h>
 #include <hostLib.h>
 #include <selectLib.h>
+/*This following is not defined in any vxWorks header files*/
+int sysClkRateGet(void);
 
 #ifdef __cplusplus
 }