XGrabKey

Syntax

XGrabKey(display, keycode, modifiers, grab_window, owner_events, pointer_mode, 
             keyboard_mode)
      Display *display;
      int keycode;
      unsigned int modifiers;
      Window grab_window;
      Bool owner_events;
      int pointer_mode, keyboard_mode;

Arguments

display Specifies the connection to the X server.
keycode Specifies the KeyCode or AnyKey.
modifiers Specifies the set of keymasks or AnyModifier. The mask is the bitwise inclusive OR of the valid keymask bits.
grab_window Specifies the grab window.
owner_events Specifies a Boolean value that indicates whether the keyboard events are to be reported as usual.
pointer_mode Specifies further processing of pointer events. You can pass GrabModeSync or GrabModeAsync.
keyboard_mode Specifies further processing of keyboard events. You can pass GrabModeSync or GrabModeAsync.

Description

The XGrabKey() function establishes a passive grab on the keyboard. In the future, the keyboard is actively grabbed (as for XGrabKeyboard()), the last-keyboard-grab time is set to the time at which the key was pressed (as transmitted in the KeyPress event), and the KeyPress event is reported if all of the following conditions are true:

The interpretation of the remaining arguments is as for XGrabKeyboard(). The active grab is terminated automatically when the logical state of the keyboard has the specified key released (independent of the logical state of the modifier keys).

Note that the logical state of a device (as seen by client applications) may lag the physical state if device event processing is frozen.

A modifiers argument of AnyModifier is equivalent to issuing the request for all possible modifier combinations (including the combination of no modifiers). It is not required that all modifiers specified have currently assigned KeyCodes. A keycode argument of AnyKey is equivalent to issuing the request for all possible KeyCodes. Otherwise, the specified keycode must be in the range specified by min_keycode and max_keycode in the connection setup, or a BadValue error results.

If some other client has issued a XGrabKey() with the same key combination on the same window, a BadAccess error results. When using AnyModifier or AnyKey, the request fails completely, and a BadAccess error results (no grabs are established) if there is a conflicting grab for any combination.

XGrabKey() can generate BadAccess , BadValue , and BadWindow errors.

Diagnostics

BadAccess A client attempted to free a color map entry that it did not already allocate.
BadAccess A client attempted to store into a read-only color map entry.
BadValue Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.
BadWindow A value for a Window argument does not name a defined Window.

See also

XAllowEvents(), XGrabButton(), XGrabKeyboard(), XGrabPointer(), XUngrabKey(), "Keyboard Grabbing".
Christophe Tronche, ch@tronche.com