MirOS Manual: XChangeActivePointerGrab(3), XGrabPointer(3), XUngrabPointer(3)


XGrabPointer(3X11)       XLIB FUNCTIONS        XGrabPointer(3X11)

NAME

     XGrabPointer, XUngrabPointer, XChangeActivePointerGrab -
     grab the pointer

SYNTAX

     int XGrabPointer(Display *display, Window grab_window, Bool
          owner_events, unsigned int event_mask, int
          pointer_mode, int keyboard_mode, Window confine_to,
          Cursor cursor, Time time);

     int XUngrabPointer(Display *display, Time time);

     int XChangeActivePointerGrab(Display *display, unsigned int
          event_mask, Cursor cursor, Time time);

ARGUMENTS

     confine_to
               Specifies the window to confine the pointer in or
               None.

     cursor    Specifies the cursor that is to be displayed dur-
               ing the grab or None.

     display   Specifies the connection to the X server.

     event_mask
               Specifies which pointer events are reported to the
               client. The mask is the bitwise inclusive OR of
               the valid pointer event mask bits.

     grab_window
               Specifies the grab window.

     keyboard_mode
               Specifies further processing of keyboard events.
               You can pass GrabModeSync or GrabModeAsync.

     owner_events
               Specifies a Boolean value that indicates whether
               the pointer events are to be reported as usual or
               reported with respect to the grab window if
               selected by the event mask.

     pointer_mode
               Specifies further processing of pointer events.
               You can pass GrabModeSync or GrabModeAsync.

     time      Specifies the time. You can pass either a times-
               tamp or CurrentTime.

DESCRIPTION

     The XGrabPointer function actively grabs control of the

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XGrabPointer(3X11)       XLIB FUNCTIONS        XGrabPointer(3X11)

     pointer and returns GrabSuccess if the grab was successful.
     Further pointer events are reported only to the grabbing
     client. XGrabPointer overrides any active pointer grab by
     this client. If owner_events is False, all generated pointer
     events are reported with respect to grab_window and are
     reported only if selected by event_mask. If owner_events is
     True and if a generated pointer event would normally be
     reported to this client, it is reported as usual. Otherwise,
     the event is reported with respect to the grab_window and is
     reported only if selected by event_mask. For either value of
     owner_events, unreported events are discarded.

     If the pointer_mode is GrabModeAsync, pointer event process-
     ing continues as usual. If the pointer is currently frozen
     by this client, the processing of events for the pointer is
     resumed. If the pointer_mode is GrabModeSync, the state of
     the pointer, as seen by client applications, appears to
     freeze, and the X server generates no further pointer events
     until the grabbing client calls XAllowEvents or until the
     pointer grab is released. Actual pointer changes are not
     lost while the pointer is frozen; they are simply queued in
     the server for later processing.

     If the keyboard_mode is GrabModeAsync, keyboard event pro-
     cessing is unaffected by activation of the grab. If the
     keyboard_mode is GrabModeSync, the state of the keyboard, as
     seen by client applications, appears to freeze, and the X
     server generates no further keyboard events until the grab-
     bing client calls XAllowEvents or until the pointer grab is
     released. Actual keyboard changes are not lost while the
     pointer is frozen; they are simply queued in the server for
     later processing.

     If a cursor is specified, it is displayed regardless of what
     window the pointer is in. If None is specified, the normal
     cursor for that window is displayed when the pointer is in
     grab_window or one of its subwindows; otherwise, the cursor
     for grab_window is displayed.

     If a confine_to window is specified, the pointer is res-
     tricted to stay contained in that window. The confine_to
     window need have no relationship to the grab_window. If the
     pointer is not initially in the confine_to window, it is
     warped automatically to the closest edge just before the
     grab activates and enter/leave events are generated as
     usual. If the confine_to window is subsequently reconfig-
     ured, the pointer is warped automatically, as necessary, to
     keep it contained in the window.

     The time argument allows you to avoid certain circumstances
     that come up if applications take a long time to respond or
     if there are long network delays. Consider a situation where

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XGrabPointer(3X11)       XLIB FUNCTIONS        XGrabPointer(3X11)

     you have two applications, both of which normally grab the
     pointer when clicked on. If both applications specify the
     timestamp from the event, the second application may wake up
     faster and successfully grab the pointer before the first
     application. The first application then will get an indica-
     tion that the other application grabbed the pointer before
     its request was processed.

     XGrabPointer generates EnterNotify and LeaveNotify events.

     Either if grab_window or confine_to window is not viewable
     or if the confine_to window lies completely outside the
     boundaries of the root window, XGrabPointer fails and
     returns GrabNotViewable. If the pointer is actively grabbed
     by some other client, it fails and returns AlreadyGrabbed.
     If the pointer is frozen by an active grab of another
     client, it fails and returns GrabFrozen. If the specified
     time is earlier than the last-pointer-grab time or later
     than the current X server time, it fails and returns GrabIn-
     validTime. Otherwise, the last-pointer-grab time is set to
     the specified time (CurrentTime is replaced by the current X
     server time).

     XGrabPointer can generate BadCursor, BadValue, and BadWindow
     errors.

     The XUngrabPointer function releases the pointer and any
     queued events if this client has actively grabbed the
     pointer from XGrabPointer, XGrabButton, or from a normal
     button press. XUngrabPointer does not release the pointer if
     the specified time is earlier than the last-pointer-grab
     time or is later than the current X server time. It also
     generates EnterNotify and LeaveNotify events. The X server
     performs an UngrabPointer request automatically if the event
     window or confine_to window for an active pointer grab
     becomes not viewable or if window reconfiguration causes the
     confine_to window to lie completely outside the boundaries
     of the root window.

     The XChangeActivePointerGrab function changes the specified
     dynamic parameters if the pointer is actively grabbed by the
     client and if the specified time is no earlier than the
     last-pointer-grab time and no later than the current X
     server time. This function has no effect on the passive
     parameters of a XGrabButton. The interpretation of
     event_mask and cursor is the same as described in XGrab-
     Pointer.

     XChangeActivePointerGrab can generate a BadCursor and Bad-
     Value error.

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XGrabPointer(3X11)       XLIB FUNCTIONS        XGrabPointer(3X11)

DIAGNOSTICS

     BadCursor A value for a Cursor argument does not name a
               defined Cursor.

     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 gen-
               erate this error.

     BadWindow A value for a Window argument does not name a
               defined Window.

SEE ALSO

     XAllowEvents(3X11), XGrabButton(3X11), XGrabKey(3X11),
     XGrabKeyboard(3X11)
     Xlib - C Language X Interface

XFree86                   Version 4.5.0                         4

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