datamsg(D3)datamsg(D3)NAMEdatamsg - test whether a message is a data message
SYNOPSIS
#include <sys/types.h>
#include <sys/stream.h>
#include <sys/ddi.h>
int datamsg(uchar_t type);
Arguments
type The type of message to be tested.
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 and 0 if the message
is any other type.
USAGE
The db_type field of the datab structure contains the message type. This
field may be accessed through the message block using mp->b_datap-
>db_type.
Level
Base or Interrupt.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function.
Examples
The put(D2) routine enqueues all data messages for handling by the
srv(D2) (service) routine. All non-data messages are handled in the put
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 }
Page 1
datamsg(D3)datamsg(D3)REFERENCESallocb(D3), datab(D4), messages(D5), msgb(D4)
Page 2
