datamsg(9F) Kernel Functions for Drivers datamsg(9F)NAMEdatamsg - test whether a message is a data message
SYNOPSIS
#include <sys/stream.h>
#include <sys/ddi.h>
int datamsg(unsigned char type);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
type 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.
DESCRIPTION
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).
RETURN VALUESdatamsg returns
1 if the message is a data message
0 otherwise.
CONTEXT
The datamsg() function can be called from user, interrupt, or kernel
context.
EXAMPLES
Example 1: 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 }
SEE ALSOput(9E), srv(9E), allocb(9F), datab(9S), msgb(9S)
Writing Device Drivers
STREAMS Programming Guide
SunOS 5.10 16 Jan 2006 datamsg(9F)