diff --git a/main.cpp b/main.cpp
index e8bd35e..b67426e 100644
--- a/main.cpp
+++ b/main.cpp
@@ -36,4 +36,5 @@ int main(int argc, char **argv) {
 
   // Finalize the MPI environment.
   MPI_Finalize();
+  return 0;
 }