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