diff --git a/src/spicelib/devices/cktaccept.c b/src/spicelib/devices/cktaccept.c
index 817f939ca..9f9227b47 100644
--- a/src/spicelib/devices/cktaccept.c
+++ b/src/spicelib/devices/cktaccept.c
@@ -8,6 +8,8 @@ Author: 1985 Thomas L. Quarles
  * this is a driver program to iterate through all the various accept
  * functions provided for the circuit elements in the given circuit */
 
+#include <string.h>
+
 #include "ngspice/config.h"
 #include "ngspice/devdefs.h"
 #include "ngspice/sperror.h"