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

OTHERQ, otherq - get pointer to queue's partner queue

#include <sys/stream.h>
#include <sys/ddi.h>
queue_t *OTHERQ(queue_t *q);

Architecture independent level 1 (DDI/DKI).

q

Pointer to the queue.

The OTHERQ() function returns a pointer to the other of the two queue structures that make up a STREAMS module or driver. If q points to the read queue the write queue will be returned, and vice versa.

The OTHERQ() function returns a pointer to a queue's partner.

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

Example 1 Setting Queues

This routine sets the minimum packet size, the maximum packet size, the high water mark, and the low water mark for the read and write queues of a given module or driver. It is passed either one of the queues. This could be used if a module or driver wished to update its queue parameters dynamically.



1 void
2 set_q_params(q, min, max, hi, lo)
3 queue_t *q;
4 short min;
5 short max;
6 ushort_t hi;
7 ushort_t lo;
8 {
9 q->q_minpsz = min; 10 q->q_maxpsz = max; 11 q->q_hiwat = hi; 12 q->q_lowat = lo; 13 OTHERQ(q)->q_minpsz = min; 14 OTHERQ(q)->q_maxpsz = max; 15 OTHERQ(q)->q_hiwat = hi; 16 OTHERQ(q)->q_lowat = lo; 17 }

Writing Device Drivers

STREAMS Programming Guide

January 16, 2006 OmniOS