backq(9r)backq(9r)NAMEbackq - STREAMS: Gets a pointer to the previous queue
SYNOPSIS
#include <sys/stream.h>
queue_t * backq(
queue_t *current_queue );
ARGUMENTS
Specifies the pointer to the current queue. The typedef queue_t is an
alternate name for struct queue_entry *.
DESCRIPTION
The backq interface returns a pointer to the queue preceding the cur‐
rent queue (the current_queue argument). If the current queue is a
read queue, backq returns a pointer to the queue downstream from the
current queue, unless the current queue is the stream end. If the cur‐
rent queue is a write queue, backq returns a pointer to the queue
upstream from the current queue, unless the current queue is the stream
head.
RETURN VALUES
Upon successful completion, the backq interface returns a pointer to
the queue preceding the current queue. Otherwise, it returns NULL.
SEE ALSO
Programmer's Guide: STREAMS
backq(9r)