Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
set_close_button_callback(3)	Allegro	manual	  set_close_button_callback(3)

NAME
       set_close_button_callback - Handles the user clicking on	the close but-
       ton 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  de-
       vice, 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. In-
       stead, 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(3)

Allegro				 version 4.4.2	  set_close_button_callback(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=set_close_button_callback&sektion=3&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help