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)
