--- lib/vpsc/csolve_VPSC.cpp
+++ lib/vpsc/csolve_VPSC.cpp
@@ -21,7 +21,9 @@
 #include <generate-constraints.h>
 #include <solve_VPSC.h>
 #include <cassert>
+#include <cstdlib>
 #include "csolve_VPSC.h"
+
 extern "C" {
 Variable* newVariable(int id, double desiredPos, double weight) {
 	return new Variable(id,desiredPos,weight);
@@ -79,7 +81,7 @@
 		vpsc->satisfy();
 	} catch(const char *e) {
 		std::cerr << e << std::endl;
-		exit(1);
+		std::exit(1);
 	}
 }
 int getSplitCnt(IncVPSC *vpsc) {