opensolaris man page for qsize

qsize(9F)						   Kernel Functions for Drivers 						 qsize(9F)

NAME
       qsize - find the number of messages on a queue

SYNOPSIS
       #include <sys/stream.h>

       int qsize(queue_t *q);

INTERFACE LEVEL
       Architecture independent level 1 (DDI/DKI).

PARAMETERS
       q    Queue to be evaluated.

DESCRIPTION
       The qsize() function evaluates the queue q and returns the number of messages it contains.

RETURN VALUES
       If  there  are  no  message  on	the queue, qsize() returns 0. Otherwise, it returns the integer representing the number of messages on the
       queue.

CONTEXT
       The qsize() function can be called from user, interrupt, or kernel context.

SEE ALSO
       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.11							    16 Jan 2006 							 qsize(9F)