The function returns the root window the pointer is logically on and the pointer coordinates relative to the root window's origin. If returns the pointer is not on the same screen as the specified window, and returns to child_return and zero to win_x_return and win_y_return. If returns the pointer coordinates returned to win_x_return and win_y_return are relative to the origin of the specified window. In this case, returns the child that contains the pointer, if any, or else to child_return.
returns the current logical state of the keyboard buttons and the modifier keys in mask_return. It sets mask_return to the bitwise inclusive OR of one or more of the button or modifier key bitmasks to match the current state of the mouse buttons and the modifier keys.
can generate a error.