qt - How to use QtSingleApplication?

Question

1. MacOSX10.8 + Qt5.1 with clang 64bit
2. Create Qt Gui application
3. in the main.cpp I just add #include <QtSingleApplication>

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Compile error:

../untitled/main.cpp:3:10: fatal error: 'QtSingleApplication' file not found
#include <QtSingleApplication>
         ^
1 error generated.
make: *** [main.o] Error 1

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What did I miss?

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Additional information
project file has already set QT += widgets

I google already, it seems need qtlocalpeer.cpp,qtlocalpeer.h,qtsingleapplication.cpp, qtsingleapplication.h,qtsinglecoreapplication.cpp,qtsinglecoreapplication.h, but how to generate these files?

some posts said it needs include qtsingleapplication.pri, but where is it? I searched my disk I cannot find it.

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reference
SinleApplication from Qt

QtSingleApplication Class Reference

Sample by Qt but where to download source code?

Answer 1

If you are looking for a better alternative to the QtSingleApplication class, especially one that works on Qt5 and supports QtQuick take a look at the SingleApplication project.

It uses QSharedMemory to ensure no race condition occur and is really easy to use. You just replace the call to QApplication with SingleApplication similar to how QtSingleApplication works:

int main(int argc, char *argv[])
{
    SingleApplication app( argc, argv );

    return app.exec();
}

It also uses Local Sockets to notify your original (first) process for the initialization of a new one so the parent can raise it's window. The dull documentation and code are available on GitHub.

Among other things it supports sending messages between the newly spawned instance and the primary instance. In this example new instances send the primary instance a message containing their arguments.

int main(int argc, char *argv[])
{
    SingleApplication app( argc, argv, true );

    if( app.isSecondary() ) {
        app.sendMessage(  app.arguments().join(' ')).toUtf8() );
        app.exit( 0 );
    }

    return app.exec();
}