datab(9S) Data Structures for Drivers datab(9S)
NAME
datab, dblk - 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 ref-
erences, 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 */
unsigned char 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 5.11 24 Oct 2003 datab(9S)
