diff --git a/tcpslice-1.2a3/util.c b/tcpslice-1.2a3/util.c

index cebaa5b..cada4c1 100644

--- a/tcpslice-1.2a3/util.c

+++ b/tcpslice-1.2a3/util.c

@@ -27,6 +27,7 @@ static const char rcsid[] =

 #include <sys/types.h>

 #include <stdio.h>

+#include <stdlib.h>

 #if __STDC__

 #include <stdarg.h>

 #else