XChangeKeyboardDevice() - change which device is used as the X keyboard
Status XChangeKeyboardDevice (Display *display, XDevice *device)
The XChangeKeyboardDevice(3) request causes the server to use the specified device as the X keyboard. The device must have been previously opened by the requesting client through XOpenDevice(3) or a BadDevice error will result. The device must support input class Keys, or a BadMatch error will result. If the server implementation does not support using the requested device as the X keyboard, a BadDevice error will result.
If the specified device is grabbed by another client, AlreadyGrabbed is returned. If the specified device is frozen by a grab on another device, GrabFrozen is returned. If the request is successful, Success is returned.
If the request succeeds, a ChangeDeviceNotify event is sent to all clients that have selected that event. A MappingNotify event with request = MappingKeyboard is sent to all clients. The specified device becomes the X keyboard and the old X keyboard becomes accessible through the input extension protocol requests.
XChangeKeyboardDevice(3) can generate a BadDevice or a BadMatch error.
Programming With Xlib