queue(9S)						    Data Structures for Drivers 						 queue(9S)

NAME

       queue - STREAMS queue structure

SYNOPSIS

       #include <sys/stream.h>

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI)

DESCRIPTION

       A   STREAMS  driver  or	module	consists  of  two   queue structures, one for upstream processing (read) and one for downstream processing
       (write). This structure is the major building block of a stream. It contains pointers to the processing procedures, pointers  to  the  next
       and  previous  queues in the stream, flow control parameters, and a pointer defining the position of its messages on the  STREAMS scheduler
       list.

       The  queue structure is defined as type	queue_t.

STRUCTURE MEMBERS

       struct	   qinit*q_qinfo;      /* module or driver entry points */
       struct	   msgb*q_first;       /* first message in queue */
       struct	   msgb*q_last;        /* last message in queue */
       struct	   queue*q_next;       /* next queue in stream */
       struct	   queue*q_link;       /* to next queue for scheduling*/
       void	   *q_ptr;	       /* pointer to private data structure */
       size_t	   q_count;	       /* approximate size of message queue */
       uint_t	   q_flag;	       /* status of queue */
       ssize_t	   q_minpsz;	       /* smallest packet accepted by QUEUE*/
       ssize_t	   q_maxpsz;	       /*largest packet accepted by QUEUE */
       size_t	   q_hiwat;	       /* high water mark */
       size_t	   q_lowat;	       /* low water mark */

       Valid flags are as follows:

       QENAB	       Queue is already enabled to run.

       QWANTR	       Someone wants to read queue.

       QWANTW	       Someone wants to write to queue.

       QFULL	       Queue is considered full.

       QREADR	       This is the reader (first) queue.

       QUSE	       This queue is in use (allocation).

       QNOENB	       Do not enable queue by way of putq().

SEE ALSO

       strqget(9F), strqset(9F), module_info(9S), msgb(9S), qinit(9S), streamtab(9S)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.10							    12 Nov 1996 							 queue(9S)