Digital

NAME

XSelectAsyncInput − Specifies an action routine and arguments to be called when some subset of events occurs. 

SYNOPSIS

XSelectAsyncInput (display, window_id, event_mask,
         ast_routine, ast_userarg)
 Display    ∗display;
 Window     window_id;
 unsigned long event_mask;
 int      (∗ast_routine)();
 unsigned long ast_userarg;

DESCRIPTION

Before calling XSelectInput to specify interest in a particular set of events for a window, clients can call XSelectAsyncInput to specify action routines and arguments to be called when some subset of those events occurs.  Xlib uses the client’s ast_routine and ast_userarg information to deliver an asynchronous event whenever it places one of the specified events on its event queue. The ast_routine and ast_userarg arguments allow the client to specify the particular action routine and parameter pair to use when notifying the client that one of the specified events has occurred. The asynchronous event acts only as an event notification mechanism; the application uses the standard Xlib event routines to actually retrieve and process the event from the event queue.  Clients can call XSelectAsyncInput multiple times to specify different routine and parameter pairs for different sets of events for a window. The last call always takes precedence.  If called with ast_routine equal to zero, asynchronous notification is disabled, but the current selection for the specified events is unaffected.  Notification events are queued in the same order as events are placed in the event queue by Xlib. Therefore, clients can assume that they receive notification events in the same order that they find events in the queue. XSelectAsyncInput is similar to XSelectAsyncEvent except that XSelectAsyncEvent specifies one event type and XSelectAsyncInput specifies an event mask. 

Arguments

displayThe display information originally returned by XOpenDisplay. 

window_idThe identifier of the window for which you want to select asynchronous input. 

event_mask
A bitmask that specifies the event types for which you want to remove an event. The mask is an inclusive OR of one or more of the event mask elements described in <REFERENCE>(event_mask_tab71).

ast_routine
The particular action routine to use when notifying the client that one of the specified events has occurred.

ast_userarg
The user-specified parameter to use when notifying the client that one of the specified events has occurred.