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)

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

NAME

       strqset - change information about a queue or band of the queue

SYNOPSIS

       #include <sys/stream.h>

       int strqset(queue_t *q, qfields_t what, unsigned char pri, intptr_t val);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       q       Pointer to the queue.

       what    Field of the queue structure (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.

       pri     Priority band of interest.

       val     The value for the field to be changed.

DESCRIPTION

       The strqset() function gives drivers and modules a way to change information about a queue or a particular band of a queue without directly
       accessing STREAMS data structures.

RETURN VALUES

       On success, 0 is returned. EINVAL is returned if an undefined attribute is specified.

CONTEXT

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

SEE ALSO

       strqget(9F), queue(9S)

       Writing Device Drivers

       STREAMS Programming Guide

NOTES

       When lowering existing values, set QMINPSZ before setting QMAXPSZ; when raising existing values, set QMAXPSZ before setting QMINPSZ.

SunOS 5.11							    16 Jan 2006 						       strqset(9F)