XGrabPointer(3X) XGrabPointer(3X)NAME XGrabPointer, XUngrabPointer, XChangeActivePointerGrab - grab and ungrab the pointer SYNOPSIS int XGrabPointer (display, grab-window, owner-events, event-mask, pointer-mode, keyboard-mode, confine-to, cursor, time) Display *display; Window grab-window; Bool owner-events; unsigned int event-mask; int pointer-mode, keyboard-mode; Window confine-to; Cursor cursor; Time time; XUngrabPointer (display, time) Display *display; Time time; XChangeActivePointerGrab (display, event-mask, cursor, time) Display *display; unsigned int event-mask; Cursor cursor; Time time; DESCRIPTION The XGrabPointer function actively grabs control of the 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 nor- mally 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 discard- ed. If pointer-mode is GrabModeAsync, pointer event processing continues as usual. If the pointer is currently frozen by this client, the processing of events for the pointer is resumed. If 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; November, 1990 1
XGrabPointer(3X) XGrabPointer(3X)they are simply queued in the server for later processing. If keyboard-mode is GrabModeAsync, keyboard event processing is unaffected by activation of the grab. If 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 grabbing 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 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 the 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 and 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 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 indication that the other application grabbed the pointer before its request was processed. XGrabPointer generates EnterNotify and LeaveNotify events. The XGrabPointer function fails and returns GrabNotViewable if grab-window or confine-to window is not viewable or if confine-to window lies completely outside the boundaries of the root window. If the pointer is actively grabbed by some other client, XGrabPointer fails and returns AlreadyGrabbed. If the pointer is frozen by an active grab of another client, XGrabPointer fails and returns Grab- Frozen. If the specified time is earlier than the last- pointer-grab time or later than the current X server time, XGrabPointer fails and returns GrabInvalidTime. Otherwise, the last-pointer-grab time is set to the specified time 2 November, 1990
XGrabPointer(3X) XGrabPointer(3X)(CurrentTime) is replaced by the current X server time). 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 XGrabPointer. Arguments These functions accept the following arguments: confine-to Specifies the window in which the pointer is to be confined, or None if it is not to be confined. cursor Specifies the pointer to be displayed during the grab or None. display Specifies the connection to the X server. event-mask Specifies which pointer events are reported to the client. They can be the bitwise inclusive OR of these pointer event mask bits: ButtonPressMask, ButtonReleaseMask, EnterWindowMask, LeaveWindowMask, PointerMotionMask, PointerMotionHintMask, Button1MotionMask, Button2MotionMask, Button3MotionMask, Button4MotionMask, Button5MotionMask, ButtonMotionMask, KeyMapStateMask. grab-window Specifies the window ID of the window relative to November, 1990 3
XGrabPointer(3X) XGrabPointer(3X)which events are reported while it is grabbed. keyboard-mode Specifies further processing of keyboard events. You can pass one of these constants: GrabModeSync or GrabModeAsync. owner-events Specifies if the pointer events are to be reported normally (pass TRUE) or with respect to the grab window if selected by the event mask (pass FALSE). pointer-mode Specifies further processing of pointer events. You can pass one of the following constants: GrabMo- deSync or GrabModeAsync. time Specifies the time. You can pass either a times- tamp, expressed in milliseconds, or CurrentTime. ERRORS BadCursor A value for a Cursor argument does not name a de- fined pointer. BadValue A numeric value falls outside the range of values accepted by the request. Unless a range is speci- fied 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 de- fined window. The XGrabPointer function can generate BadCursor, BadValue, and BadWindow errors. The XChangeActivePointerGrab function can generate BadCursor and BadValue errors. SEE ALSO XAllowEvents(3X), XGrabButton(3X), XGrabKey(3X), XGrabKeyboard(3X)Xlib - C Language Interface4 November, 1990