Add singleapplication

GPClient/GPClient.pro

@@ -4,6 +4,9 @@ greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
 CONFIG += c++11
 
+include(../singleapplication/singleapplication.pri)
+DEFINES += QAPPLICATION_CLASS=QApplication
+
 # The following define makes your compiler emit warnings if you use
 # any Qt feature that has been marked deprecated (the exact warnings
 # depend on your compiler). Please consult the documentation of the

GPClient/main.cpp

@@ -1,11 +1,13 @@
+#include "singleapplication.h"
 #include "gpclient.h"
 
-#include <QApplication>
-
 int main(int argc, char *argv[])
 {
-    QApplication a(argc, argv);
+    SingleApplication app(argc, argv);
     GPClient w;
     w.show();
-    return a.exec();
+
+    QObject::connect(&app, &SingleApplication::instanceStarted, &w, &GPClient::raise);
+
+    return app.exec();
 }