diff --git a/hss.hpp b/hss.hpp
index 2f654fa..9e9cc94 100644
--- a/hss.hpp
+++ b/hss.hpp
@@ -1,3 +1,5 @@
+#ifndef _HSS_HPP
+#define _HSS_HPP
 #include <iostream>
 #include <string>
 #include <unistd.h>
@@ -6,8 +8,9 @@
 
 
 namespace HSS {
-inline void run(QBiIPC& ipc, const std::string& file) {
-    if (fork() == 0) {
+inline pid_t run(QBiIPC& ipc, const std::string& file) {
+    auto pid = fork();
+    if (pid == 0) {
         execlp("HSSChildLauncher", "child",
                std::to_string(ipc.out.get_in()).c_str(),
                std::to_string(ipc.out.get_out()).c_str(),
@@ -18,5 +21,7 @@ inline void run(QBiIPC& ipc, const std::string& file) {
         std::cerr << "Failed to run HSSChildLauncher" << std::endl;
         abort();
     }
+    return pid;
 }
 }
+#endif