1set_close_button_callback(3)    Allegro manual    set_close_button_callback(3)
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NAME

6       set_close_button_callback - Handles the user clicking on the close but‐
7       ton of the window. Allegro game programming library.
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SYNOPSIS

10       #include <allegro.h>
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13       int set_close_button_callback(void (*proc)(void));
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DESCRIPTION

16       On platforms that have a close button, this routine installs a callback
17       function  to  handle  the  close  event.  In other words, when the user
18       clicks the close button on your  program's  window  or  any  equivalent
19       device, the function you specify here will be called.
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21       This  function should not generally attempt to exit the program or save
22       any data itself. The function could be called at any time, and there is
23       usually  a  risk  of  conflict  with  the  main  thread of the program.
24       Instead, you should set a flag during this function, and test it  on  a
25       regular basis in the main loop of the program.
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27       Pass  NULL as the `proc' argument to this function to disable the close
28       button functionality, which is the default state.
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30       Note that Allegro cannot intercept the close button of  a  DOS  box  in
31       Windows.
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33       Also  note that the supplied callback is also called under MacOS X when
34       the user hits Command-Q or selects "Quit" from  the  application  menu.
35       Example:
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37          volatile int close_button_pressed = FALSE;
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39          void close_button_handler(void)
40          {
41             close_button_pressed = TRUE;
42          }
43          END_OF_FUNCTION(close_button_handler)
44          ...
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46          allegro_init();
47          LOCK_FUNCTION(close_button_handler);
48          set_close_button_callback(close_button_handler);
49          ...
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51          while (!close_button_pressed)
52             do_stuff();
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RETURN VALUE

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

60       set_window_title(3)
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64Allegro                          version 4.4.3    set_close_button_callback(3)
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