qband(9s) [opensolaris man page]

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

NAME

       qband - STREAMS queue flow control information structure

SYNOPSIS

       #include <sys/stream.h>

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI)

DESCRIPTION

       The  qband structure contains flow control information for each priority band in a queue.

       The qband structure is defined as type qband_t.

STRUCTURE MEMBERS

	 struct        qband*qb_next;	  /* next band's info */
	 size_t        qb_count 	  /* number of bytes in band */
	 struct msgb   *qb_first;	  /* start of band's data */
	 struct msgb   *qb_last;	  /* end of band's data */
	 size_t        qb_hiwat;	  /* band's high water mark */
	 size_t        qb_lowat;	  /* band's low water mark */
	 uint_t        qb_flag; 	  /* see below */

       Valid flags are as follows:

       QB_FULL	    Band is considered full.

       QB_WANTW     Someone wants to write to band.

SEE ALSO

       strqget(9F), strqset(9F), msgb(9S), queue(9S)

       STREAMS Programming Guide

NOTES

       All access to this structure should be through strqget(9F) and strqset(9F). It is logically part of the queue(9S) and its layout and parti-
       tioning with respect to that structure might change in future releases. If portability is a concern, do not declare or store  instances	of
       or references to this structure.

SunOS 5.11							    14 Nov 1996 							 qband(9S)

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

NAME

       strqget - get information about a queue or band of the queue

SYNOPSIS

       #include <sys/stream.h>

       int strqget(queue_t *q, qfields_t what, unsigned char pri, void *valp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       q	Pointer to the queue.

       what	Field of the queue structure for (or the specified priority band) to return information about. Valid values are one of:

		QHIWAT		High water mark.

		QLOWAT		Low water mark.

		QMAXPSZ 	Largest packet accepted.

		QMINPSZ 	Smallest packet accepted.

		QCOUNT		Approximate size (in bytes) of data.

		QFIRST		First message.

		QLAST		Last message.

		QFLAG		Status.

       pri	Priority band of interest.

       valp	The address of where to store the value of the requested field.

DESCRIPTION

       strqget()  gives  drivers  and  modules	a  way to get information about a queue or a particular band of a queue without directly accessing
       STREAMS data structures, thus insulating them from changes in the implementation of these data structures from release to release.

RETURN VALUES

       On success, 0 is returned and the value of the requested field is stored in the location pointed to by valp. An error number is returned on
       failure.

CONTEXT

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

SEE ALSO

       strqset(9F), queue(9S)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.10							    17 Oct 2000 						       strqget(9F)