msgb(D4str)

Synopsis

   #include <sys/types.h>
   #include <sys/stream.h>
   #include <sys/ddi.h>

Description

Usage

Structure definitions

   struct msgb	*b_next;
   struct msgb	*b_prev;
   struct msgb	*b_cont;
   uchar_t	*b_rptr;
   uchar_t	*b_wptr;
   struct datab	*b_datap;
   uchar_t	b_band;
   ushort_t	b_flag;

Structure members

b_next and b_prev

pointers that are used to link messages together on a queue(D4str). These members can be used by drivers and modules to create linked lists of messages.

b_cont

links message blocks together when a message is composed of more than one block. Drivers and modules can use this member to create complex messages from single message blocks.

b_rptr and b_wptr

describe the valid data region in the associated data buffer. The b_rptr member points to the first unread byte in the buffer and the b_wptr member points to the next byte to be written in the buffer.

b_datap

points to the datab(D4str) data block that is associated with the message block. Modules and drivers must not change this member.

b_band

contains the priority band associated with the message. Normal priority messages and high priority messages have b_band set to zero. High priority messages are high priority by virtue of their message type. This member can be used to alter the queuing priority of the message. The higher the priority band, the closer to the head of the queue the message is placed.

b_flag

contains a bitmask of flags that can be set to alter the way the stream head will process the message. Valid flags are:

MSGMARK

The last byte in the message is ``marked.'' This condition is testable from user level with I_ATMARK.

Hardware applicability

Version applicability

References