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).

ARGUMENTS

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

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