Re: interrupting a big loop

On Wed, 19 May 2004, Tristan Van Berkom wrote:

Allin Cottrell wrote:
Thank you, this is just the sort of thing I was groping for.  I have
one more question.

    /* It is possible that your callback
     * `on_cancel_button_clicked()' was called
     * during `gtk_main_iteration()'.
    if (should_stop == TRUE) break;

What's the best way of implementing this?  Make "should_stop" a global
boolean that is initially set to FALSE, and is set TRUE within the
cancel button callback?  Or can one avoid a global?

You could beat around the bush a little, like this:

on_cancel_button_clicked(cancel_button, ... data) {
     gboolean *should_stop = data;
     if (should_stop)
         *should_stop = TRUE;

expensive_callback(some_object... data) {
     gboolean should_stop;
     gulong        sigid;
     should_stop = FALSE;
     sigid = g_signal_connect(cancel_button, "clicked",
                              on_cancel_button_clicked, &should_stop);
     for (;;) {
         /* ...
         if (*should_stop) break;
         /* ...
     g_signal_disconnect(cancel_button, sigid);

But that is a little meticulous wouldn't you say ?

Yes, I would ;-)

The global state variable works fine.

Allin Cottrell

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