qunbufcall() cancels a pending qbufcall() request. The argument id is a non-zero identifier of the request to be cancelled. id is returned from the qbufcall() function used to issue the cancel request.
The qunbufcall() function is tailored to be used with the enhanced STREAMS framework interface which is based on the concept of perimeters. (See
mt-streams(9F).) qunbufcall() returns when the bufcall has been
cancelled or finished executing. The bufcall will be cancelled even if it is blocked at the perimeters associated with the queue. All outstanding bufcalls should be cancelled before the driver closes or