WR(D3)WR(D3)NAME
WR - get a pointer to the write queue
SYNOPSIS
#include <sys/stream.h>
#include <sys/ddi.h>
queue_t *WR(queue_t *q);
Arguments
q Pointer to the queue whose write queue is to be returned.
DESCRIPTION
The WR function accepts a queue pointer as an argument and returns a
pointer to the write queue of the same module.
Return Values
The pointer to the write queue.
USAGE
Note that when WR is passed a write queue pointer as an argument, it
returns a pointer to this write queue.
Level
Base or Interrupt.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function.
Examples
In a STREAMS open(D2) routine, the driver or module is passed a pointer
to the read queue. The driver or module can store a pointer to a private
data structure in the q_ptr field of both the read and write queues if it
needs to identify the data structures from its put(D2) or srv(D2)
routines.
1 extern struct xxx_dev[];
...
2 xxxopen(queue_t *q, dev_t *devp, int flag, int sflag, cred_t *crp)
3 {
...
3 q->q_ptr = (caddr_t)&xxx_dev[getminor(*devp)];
4 WR(q)->q_ptr = (caddr_t)&xxx_dev[getminor(*devp)];
...
5 }
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WR(D3)WR(D3)REFERENCESOTHERQ(D3), RD(D3)
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