'\" te
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.TH bcanput 9F "16 Jan 2006" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
bcanput \- test for flow control in specified priority band
.SH SYNOPSIS
.LP
.nf
#include <sys/stream.h>



\fBint\fR \fBbcanput\fR(\fBqueue_t *\fR\fIq\fR, \fBunsigned char\fR \fIpri\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Architecture independent level 1 (DDI/DKI).
.SH PARAMETERS
.sp
.ne 2
.mk
.na
\fB\fIq\fR\fR
.ad
.RS 7n
.rt  
Pointer to the message queue.
.RE

.sp
.ne 2
.mk
.na
\fB\fIpri\fR\fR
.ad
.RS 7n
.rt  
Message priority.
.RE

.SH DESCRIPTION
.sp
.LP
The \fBbcanput()\fR function searches through the stream (starting at \fIq\fR)
until it finds a queue containing a service routine where the message can be
enqueued, or until it reaches the end of the stream. If found, the queue
containing the service routine is tested to see if there is room for a message
of priority \fIpri\fR in the queue.
.sp
.LP
If \fIpri\fR is \fB0\fR, \fBbcanput()\fR is equivalent to a call with
\fBcanput\fR(9F).
.sp
.LP
\fBcanputnext(\fR\fIq\fR\fB)\fR and
\fBbcanputnext(\fR\fIq\fR\fB,\fR\fIpri\fR\fB)\fR should always be used in
preference to \fBcanput(\fR\fIq\fR\fB\(->q_next)\fR and
\fBbcanput(\fR\fIq\fR\fB\(->q_next,\fR\fIpri\fR\fB)\fR respectively.
.SH RETURN VALUES
.sp
.ne 2
.mk
.na
\fB\fB1\fR\fR
.ad
.RS 5n
.rt  
If a message of priority \fIpri\fR can be placed on the queue.
.RE

.sp
.ne 2
.mk
.na
\fB\fB0\fR\fR
.ad
.RS 5n
.rt  
If the priority band is full.
.RE

.SH CONTEXT
.sp
.LP
The \fBbcanput()\fR function can be called from user, interrupt, or kernel
context.
.SH SEE ALSO
.sp
.LP
\fBbcanputnext\fR(9F), \fBcanput\fR(9F), \fBcanputnext\fR(9F), \fBputbq\fR(9F),
\fBputnext\fR(9F)
.sp
.LP
\fIWriting Device Drivers\fR
.sp
.LP
\fISTREAMS Programming Guide\fR
.SH WARNINGS
.sp
.LP
Drivers are responsible for both testing a queue with \fBbcanput()\fR and
refraining from placing a message on the queue if \fBbcanput()\fR fails.