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Kernel Functions for Drivers

WR(9F)

INTERFACE LEVEL
PARAMETERS
DESCRIPTION
RETURN VALUES
CONTEXT
EXAMPLES
SEE ALSO

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.

CONTEXT

WR() can be called from user or interrupt context.

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 }