--- a/src/tctool.cpp
+++ b/src/tctool.cpp
@@ -33,6 +33,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <signal.h>
+#include <cstdlib>
 
 std::string                      options = "I:m:i:r:t:p:c:MUdsSCRh";
 std::string                      ethDev  = "eth0";