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Data Structures for Driversdatab(9S)


NAME

 datab - STREAMS message data structure

SYNOPSIS

 
#include <sys/stream.h>

INTERFACE LEVEL

 

Architecture independent level 1 (DDI/DKI).

DESCRIPTION

 

The datab structure describes the data of a STREAMS message. The actual data contained in a STREAMS message is stored in a data buffer pointed to by this structure. A msgb (message block) structure includes a field that points to a datab structure.

Because a data block can have more than one message block pointing to it at one time, the db_ref member keeps track of a data block's references, preventing it from being deallocated until all message blocks are finished with it.

STRUCTURE MEMBERS

 

 
unsigned char     *db_base;     /* first byte of buffer */
unsigned char     *db_lim;      /* last byte (+1) of buffer */
dbref_t           db_ref;       /* # of message pointers to this data */
unsigned char     db_type;      /* message type */

A datab structure is defined as type dblk_t.

SEE ALSO

 

free_rtn(9S), msgb(9S)

Writing Device Drivers

STREAMS Programming Guide


SunOS 5.9Go To TopLast Changed 18 Feb 1998

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.