opensolaris man page for backq

backq(9F)						   Kernel Functions for Drivers 						 backq(9F)

NAME
       backq - get pointer to the queue behind the current queue

SYNOPSIS
       #include <sys/stream.h>

       queue_t *backq(queue_t *cq);

INTERFACE LEVEL
       Architecture independent level 1 (DDI/DKI).

PARAMETERS
       cq    The pointer to the current queue.	 queue_t is an alias for the queue(9S) structure.

DESCRIPTION
       The  backq()  function returns a pointer to the queue preceding cq (the current queue). If cq is a read queue, backq() returns a pointer to
       the queue downstream from cq, unless it is the stream end. If cq is a write queue, backq() returns a pointer to	the  next  queue  upstream
       from cq, unless it is the stream head.

RETURN VALUES
       If successful, backq() returns a pointer to the queue preceding the current queue. Otherwise, it returns NULL.

CONTEXT
       The backq() function can be called from user, interrupt, or kernel context.

SEE ALSO
       queue(9S)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.11							    16 Jan 2006 							 backq(9F)