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canputnext (9)

>> canputnext (9) ( Solaris man: Ядро )

NAME

canputnext, bcanputnext - test for room in next module's message queue

SYNOPSIS

#include <sys/stream.h>

int canputnext(queue_t *q);

int bcanputnext(queue_t *q, unsigned char pri);

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

PARAMETERS

q Pointer to a message queue belonging to the invoking module.

pri Minimum priority level.

DESCRIPTION

The invocation canputnext(q); is an atomic equivalent of the canput(q->q_next); routine. That is, the STREAMS framework provides whatever mutual exclusion is necessary to insure that dereferencing q through its q_next field and then invoking canput(9F) proceeds without interference from other threads.

bcanputnext(q, pri); is the equivalent of the bcanput(q->q_next, pri); routine.

canputnext(q); and bcanputnext(q, pri); should always be used in preference to canput(q->q_next); and bcanput(q->q_next, pri); respectively.

See canput(9F) and bcanput(9F) for further details.

RETURN VALUES

1 If the message queue is not full.

0 If the queue is full.

CONTEXT

The canputnext() and bcanputnext() functions can be called from user, interrupt, or kernel context.

WARNINGS

Drivers are responsible for both testing a queue with canputnext() or bcanputnext() and refraining from placing a message on the queue if the queue is full.