On 27 Apr 2011, at 16:33, chris tyt wrote:
> void sleepcb(Fl_Widget *, void *)
> {
> b1->deactivate();
> Fl::flush();
>
> sleep(3);
I don't think your use of sleep() here is valid - it's a blocking call, so you
will block the fltk event handling *whilst you are inside a callback event* and
then all bets are off.
You want to try using a fl_timer to set/clear the button state, and see if the
effect is still present.
See amended code below...
>
> Fl::flush();
> b1->activate();
> }
Anyway, in general, DO NOT do long calculations in a callback, or any sort of
blocking operation, as that *will* break the event handling.
If you must do long calculations, contrive to pump the event loop by calling
Fl::check() from time to time. (Though that obviously does not help for
blocking calls.)
If you *need* to make blocking calls, look into using timer callbacks, or
Fl::add_fd() to handle pipe/socket events, or use a thread.
Don't ever stick them into a callback, as that will always bite you at some
point!
/* revised code */
#include <stdio.h>
#include <unistd.h>
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Button.H>
Fl_Button* b1;
void hellocb(Fl_Widget *, void *) {
printf("hello\n");
}
void timercb(void*) {
b1->activate();
}
void sleepcb(Fl_Widget *, void *) {
b1->deactivate();
Fl::add_timeout(3.0, timercb);
}
int main( int argc, char** argv) {
Fl_Window *window = new Fl_Window(320,65);
b1 = new Fl_Button(20,20, 200, 25, "hello");
Fl_Button *b2 = new Fl_Button(220,20, 80, 25, "sleep(3)");
b1->callback(hellocb,0);
b2->callback(sleepcb,0);
window->end();
window->show();
return Fl::run();
}
/* end of code */
_______________________________________________
fltk mailing list
[email protected]
http://lists.easysw.com/mailman/listinfo/fltk
