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Copyright 1989 AT&T
Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved
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DATAMSG 9F "Jan 16, 2006"
NAME
datamsg - 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 VALUES

datamsg 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

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 ALSO

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

Writing Device Drivers

STREAMS Programming Guide