NAME
XGrabPointer, XUngrabPointer, XChangeActivePointerGrab - grab the pointer SYNTAX int XGrabPointer(Display *display, Window grabwindow, Bool ownerevents, unsigned int eventmask, int pointermode, int keyboardmode, Window confineto, Cursor cursor, Time time); int XUngrabPointer(Display *display, Time time); int XChangeActivePointerGrab(Display *display, unsigned int eventmask, Cursor cursor, Time time); ARGUMENTS confineto Specifies the window to confine the pointer in or None. cursor Specifies the cursor that is to be displayed during the grab or None. display Specifies the connection to the X server. eventmask Specifies which pointer events are reported to the client. The mask is the bitwise inclusive OR of the valid pointer event mask bits. grabwindow Specifies the grab window. keyboardmode Specifies further processing of keyboard events. You can pass GrabModeSync or GrabModeAsync. ownerevents 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. pointermode Specifies further processing of pointer events. You can pass GrabModeSync or GrabModeAsync. time Specifies the time. You can pass either a timestamp or Cur‐ rentTime. 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 ownerevents is False, all gen‐ erated pointer events are reported with respect to grabwindow and are reported only if selected by eventmask. If ownerevents 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 grabwindow and is reported only if selected by eventmask. For either value of ownerevents, unreported events are discarded. If the pointermode is GrabModeAsync, pointer event processing contin‐ ues as usual. If the pointer is currently frozen by this client, the processing of events for the pointer is resumed. If the pointermode is GrabModeSync, the state of the pointer, as seen by client applica‐ tions, 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 keyboardmode is GrabModeAsync, keyboard event processing is unaffected by activation of the grab. If the keyboardmode is GrabMod‐ eSync, 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 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 grabwindow or one of its subwin‐ dows; otherwise, the cursor for grabwindow is displayed. If a confineto window is specified, the pointer is restricted to stay contained in that window. The confineto window need have no relation‐ ship to the grabwindow. If the pointer is not initially in the con‐ fineto window, it is warped automatically to the closest edge just before the grab activates and enter/leave events are generated as usual. If the confineto window is subsequently reconfigured, 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 applica‐ tion 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. Either if grabwindow or confineto window is not viewable or if the confineto 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 Already‐ Grabbed. 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 GrabInvalidTime. Otherwise, the last-pointer-grab time is set to the specified time (CurrentTime is replaced by the cur‐ rent 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 confineto window for an active pointer grab becomes not viewable or if window reconfiguration causes the confineto 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 eventmask and cursor is the same as described in XGrabPointer. XChangeActivePointerGrab can generate a BadCursor and BadValue error. 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 generate this error. BadWindow A value for a Window argument does not name a defined Window. SEE ALSO XAllowEvents(3), XGrabButton(3), XGrabKey(3), XGrabKeyboard(3)
Xlib - C Language X Interface X Version 11 libX11 1.6.5 XGrabPointer(3)