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

datamsg - test whether a message is a data message

#include <sys/stream.h>
#include <sys/ddi.h>
int datamsg(unsigned char type);

Architecture independent level 1 (DDI/DKI).

The type of message to be tested. The db_type field of the datab(9S) structure contains the message type. This field may be accessed through the message block using mp->b_datap->db_type.

The datamsg() function tests the type of message to determine if it is a data message type (M_DATA, M_DELAY, M_PROTO , or M_PCPROTO).

datamsg returns


if the message is a data message



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

The put(9E) routine enqueues all data messages for handling by the srv(9E) (service) routine. All non-data messages are handled in the put(9E) routine.

1 xxxput(q, mp)
2      queue_t *q;
3      mblk_t *mp;
4 {
5    if (datamsg(mp->b_datap->db_type)) {
6            putq(q, mp);
7            return;
8    }
9    switch (mp->b_datap->db_type) {
10    case M_FLUSH:
11    }
12 }

put(9E), srv(9E), allocb(9F), datab(9S), msgb(9S)

Writing Device Drivers

STREAMS Programming Guide

January 16, 2006 OmniOS