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Kernel Functions for Driversputnextctl1(9F)


NAME

 putnextctl1 - send a control message with a one-byte parameter to a queue

SYNOPSIS

 
#include <sys/stream.h>
int putnextctl1(queue_t *q, int type, int p);

INTERFACE LEVEL

 

Architecture independent level 1 (DDI/DKI).

PARAMETERS

 
q
Queue to which the message is to be sent.
type
Type of message.
p
One-byte parameter.

DESCRIPTION

 

putnextctl1(), like putctl1(9F), tests the type argument to make sure a data type has not been specified, and attempts to allocate a message block. The p parameter can be used, for example, to specify how long the delay will be when an M_DELAY message is being sent. putnextctl1() fails if type is M_DATA, M_PROTO, or M_PCPROTO, or if a message block cannot be allocated. If successful, putnextctl1() calls the put(9E) routine of the queue pointed to by q with the newly allocated and initialized message.

A call to putnextctl1(q,type, p) is an atomic equivalent of putctl1(q->q_next, type, p). The STREAMS framework provides whatever mutual exclusion is necessary to insure that dereferencing q through its q_next field and then invoking putctl1(9F) proceeds without interference from other threads.

putnextctl1() should always be used in preference to putctl1(9F)

RETURN VALUES

 

On success, 1 is returned. 0 is returned if type is a data type, or if a message block cannot be allocated.

CONTEXT

 

putnextctl1() can be called from user or interrupt context.

EXAMPLES

 

See the putnextctl(9F) function page for an example of putnextctl1().

SEE ALSO

 

put(9E), allocb(9F), datamsg(9F), putctl1(9F), putnextctl(9F)

Writing Device Drivers

STREAMS Programming Guide


SunOS 5.9Go To TopLast Changed 29 Mar 1993

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.