the #GdkWindow which will own the grab
capabilities that will be grabbed
if %FALSE then all device events are reported with respect to @window and are only reported if selected by @event_mask. If %TRUE then pointer events for this application are reported as normal, but pointer events outside this application are reported with respect to @window and only if selected by @event_mask. In either mode, unreported events are discarded.
the cursor to display while the grab is active. If this is %NULL then the normal cursors are used for @window and its descendants, and the cursor for @window is used elsewhere.
the event that is triggering the grab, or %NULL if none is available.
function to prepare the window to be grabbed, it can be %NULL if @window is visible before this call.
user data to pass to @prepare_func
Return: %GDK_GRAB_SUCCESS if the grab was successful.
3.20
Grabs the seat so that all events corresponding to the given @capabilities are passed to this application until the seat is ungrabbed with gdk_seat_ungrab(), or the window becomes hidden. This overrides any previous grab on the seat by this client.
As a rule of thumb, if a grab is desired over %GDK_SEAT_CAPABILITY_POINTER, all other "pointing" capabilities (eg. %GDK_SEAT_CAPABILITY_TOUCH) should be grabbed too, so the user is able to interact with all of those while the grab holds, you should thus use %GDK_SEAT_CAPABILITY_ALL_POINTING most commonly.
Grabs are used for operations which need complete control over the events corresponding to the given capabilities. For example in GTK+ this is used for Drag and Drop operations, popup menus and such.
Note that if the event mask of a #GdkWindow has selected both button press and button release events, or touch begin and touch end, then a press event will cause an automatic grab until the button is released, equivalent to a grab on the window with @owner_events set to %TRUE. This performed as most applications expect to receive presses and releases in pairs.
If you set up anything at the time you take the grab that needs to be cleaned up when the grab ends, you should handle the #GdkEventGrabBroken events that are emitted when the grab ends unvoluntarily.