Beginner Question: Changing the Text of a Button

[Chris Share <cpsmusic yahoo com>]

Hi,

I'm a complete beginner with respect to gtk and gtkmm.

I'd like to add a gtkmm gui to a command line application that I've developed.

As a starting point, I've created a simple demo app with a button. I'd like to change the button's text each time it's clicked.

The button is declared in the app's main window as

Gtk::Button start;

When it's clicked I'd like to change its text as shown below:

void MainWindow::on_play_button_clicked() {

    

    std::cout << "Play" << std::endl;

    

    if(state == 0) {

        gtk_button_set_label(GTK_BUTTON(start), "Stop");

    } else {

 gtk_button_set_label(GTK_BUTTON(start), "Start");

    }

}

What I can't figure out is the actual code to get this to work.

When I build the code I get the following error:

MainWindow.cpp: In member function ‘void MainWindow::on_play_button_clicked()’:

MainWindow.cpp:31: error: invalid cast from type ‘Gtk::Button’ to type ‘GTypeInstance*’

make: *** [metro] Error 1

What am I doing wrong here?

Cheers,

Chris