diff --git a/src/libCom/misc/epicsString.h b/src/libCom/misc/epicsString.h
index 09480906e..6da7260fa 100644
--- a/src/libCom/misc/epicsString.h
+++ b/src/libCom/misc/epicsString.h
@@ -16,6 +16,7 @@
  * returns the length of the resultant string (may contain nulls)
 */
 
+#include <stdio.h>
 #include <shareLib.h>
 
 #ifdef __cplusplus