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  {
 5q->q_ptr = NULL;
 6WR(q)->q_ptr = NULL;
. . .
 7  }

SEE ALSO

OTHERQ(9F), RD(9F)

Writing Device Drivers
STREAMS Programming Guide

SunOS 5.5/SPARC  —  Last change: 15 Nov 1991