_userproc()application-level function, or hook. The CSA library routines tell
_userproc()whether it is being called as an Input Hook or an Output Hook by passing it the flag
_O_RESPONSErespectively, so that the function knows what to do. Refer to the
$CSA_INSTALL/lib/csa-rpciolib.awkfile for an example of a dummy input/output hook.