The function sets the mapping of the pointer. If it succeeds, the X server generates a event, and returns Element map[i] defines the logical button number for the physical button i+1. The length of the list must be the same as would return, or a error results. A zero element disables a button, and elements are not restricted in value by the number of physical buttons. However, no two elements can have the same nonzero value, or a error results. If any of the buttons to be altered are logically in the down state, returns and the mapping is not changed.
can generate a error.
The function returns the current mapping of the pointer. Pointer buttons are numbered starting from one. returns the number of physical buttons actually on the pointer. The nominal mapping for a pointer is map[i]=i+1. The nmap argument specifies the length of the array where the pointer mapping is returned, and only the first nmap elements are returned in map_return.