WR(9F) Kernel Functions for Drivers WR(9F)
NAME
WR, wr - get pointer to the write queue for this module or driver
SYNOPSIS
#include <sys/stream.h>
#include <sys/ddi.h>
queue_t *WR(queue_t *q);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
q Pointer to the read queue whose write queue is to be returned.
DESCRIPTION
The WR() function accepts a read queue pointer as an argument and returns a pointer to the write queue of the same module.
CAUTION: Make sure the argument to this function is a pointer to a read queue. WR() will not check for queue type, and a system panic could
result if the pointer is not to a read queue.
RETURN VALUES
The pointer to the write queue.
CONTEXT
WR() can be called from user or interrupt context.
EXAMPLES
Example 1: Using WR()
In a STREAMS close(9E) routine, the driver or module is passed a pointer to the read queue. These usually are set to the address of the
module-specific data structure for the minor device.
1 xxxclose(q, flag)
2 queue_t *q;
3 int flag;
4 {
5 q->q_ptr = NULL;
6 WR(q)->q_ptr = NULL;
. . .
7 }
SEE ALSO
close(9E), OTHERQ(9F), RD(9F)
Writing Device Drivers
STREAMS Programming Guide
SunOS 5.10 15 Nov 1991 WR(9F)
