This function allows for hooking into the operation
of getting the current location of the pointer on a particular
display. This is only useful for such low-level tools as an
event recorder. Applications should never have any
reason to use this facility.
[GdkDisplayPointerHooks] a table of pointers to functions for getting
quantities related to the current pointer position,
or NULL to restore the default table.
Value
[GdkDisplayPointerHooks] the previous pointer hook table