datab(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.

A data block can have more than one message block pointing to it at one time, so 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 ∗/
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.

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