blog: jl_signal, code: usage example

gistfile1.cpp

// Declare and instantiate a signal for functions that take a
// single char arg.
JL_SIGNAL( char ) oKeyPressSignal;

// Two objects of unrelated type.
Piano oPiano; // plays notes
Transcriber oTranscriber; // generates text logs

// Lets assume the following instance method declarations:
//
// void Piano::PlayNote( char nKey );
// void Transcriber::LogInput( char c );
//
// Now let's connect these objects to oKeyPressSignal:
oKeyPressSignal.connect( &oPiano, &Piano::PlayNote );
oKeyPressSignal.connect( &oTranscriber, &Transcriber::LogInput );

for (;;)
{
    // Gather user input.
    char nKey = getchar();
    
    // Terminate if the user presses ENTER.
    if (nKey == 10)
    {
        break;
    }

    // Now let's emit the signal with the user's input. This is the
    // equivalent of making the following function calls:
    //
    //     oPiano.PlayNote( nKey );
    //     oTranscriber.LogInput( nKey );
    oKeyPressSignal.Emit( nKey );
}