NAME

       set_close_button_callback  -  Handles  the  user clicking on the close button of the window. Allegro game
       programming library.

SYNOPSIS

       #include <allegro.h>

       int set_close_button_callback(void (*proc)(void));

DESCRIPTION

       On platforms that have a close button, this routine installs a callback  function  to  handle  the  close
       event.  In  other words, when the user clicks the close button on your program's window or any equivalent
       device, the function you specify here will be called.

       This function should not generally attempt to exit the program or save  any  data  itself.  The  function
       could be called at any time, and there is usually a risk of conflict with the main thread of the program.
       Instead, you should set a flag during this function, and test it on a regular basis in the main  loop  of
       the program.

       Pass NULL as the `proc' argument to this function to disable the close button functionality, which is the
       default state.

       Note that Allegro cannot intercept the close button of a DOS box in Windows.

       Also note that the supplied callback is also called under MacOS X when the user hits Command-Q or selects
       "Quit" from the application menu.  Example:

          volatile int close_button_pressed = FALSE;

          void close_button_handler(void)
          {
             close_button_pressed = TRUE;
          }
          END_OF_FUNCTION(close_button_handler)
          ...

          allegro_init();
          LOCK_FUNCTION(close_button_handler);
          set_close_button_callback(close_button_handler);
          ...

          while (!close_button_pressed)
             do_stuff();

RETURN VALUE

       Returns zero on success and non-zero on failure (e.g. the feature is not supported by the platform).

SEE ALSO

       set_window_title(3alleg4)