gui: single instance mode.

3rd/SingleApplication-3.5.2/examples/basic/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.7.0)
+
+project(basic LANGUAGES CXX)
+
+# SingleApplication base class
+set(QAPPLICATION_CLASS QCoreApplication)
+add_subdirectory(../.. SingleApplication)
+
+add_executable(basic main.cpp)
+
+target_link_libraries(${PROJECT_NAME} SingleApplication::SingleApplication)
+

3rd/SingleApplication-3.5.2/examples/basic/basic.pro

@@ -0,0 +1,5 @@
+# Single Application implementation
+include(../../singleapplication.pri)
+DEFINES += QAPPLICATION_CLASS=QCoreApplication
+
+SOURCES += main.cpp

3rd/SingleApplication-3.5.2/examples/basic/main.cpp

@@ -0,0 +1,33 @@
+// Copyright (c) Itay Grudev 2015 - 2023
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// Permission is not granted to use this software or any of the associated files
+// as sample data for the purposes of building machine learning models.
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include <singleapplication.h>
+
+int main(int argc, char *argv[])
+{
+    SingleApplication app( argc, argv );
+
+    qWarning() << "Started a new instance";
+
+    return app.exec();
+}