message queue problem

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bcanput

bcanput(9r)															       bcanput(9r)

NAME

       bcanput - STREAMS: Tests for flow control in a specified priority band

SYNOPSIS

       #include <sys/stream.h>

       int bcanput(
	       queue_t *message_queue,
	       unsigned char pri );

ARGUMENTS

       Specifies a pointer to the message queue. The typedef queue_t is an alternate name for struct queue_entry *.  Specifies the priority of the
       message.

DESCRIPTION

       The bcanput interface, like the canput interface, searches through the stream (starting	at  the  message  queue  identified  by  the  mes-
       sage_queue argument) until it finds a queue that contains a service interface where the message can be enqueued or until it reaches the end
       of the stream. If bcanput finds a service interface in a queue, it tests the queue to determine if there is space in the queue to  accommo-
       date  a	message. If the queue is full, bcanput sets the q_flag member of the queue_entry structure pointer (the message queue) to the con-
       stant QWANTW to back-enable the caller's service interface.

       If the pri argument is zero(0), bcanput calls the canput interface, which performs the task of checking for space in the message queue.

NOTES

       You are responsible for both testing a queue with bcanput and not placing a message on the queue if bcanput fails.

RETURN VALUES

       The bcanput interface returns a value of 1 if a message of priority pri can be placed on the message queue, or if the  band  does  not  yet
       exist on the queue. The interface returns a value of zero(0) if the priority band is flow-controlled.

SEE ALSO

       Kernel Routines: canput(9r), putbq(9r), putnext(9r)

       Programmer's Guide: STREAMS

																       bcanput(9r)

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