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

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

       datamsg() 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

       datamsg() can be called from user or interrupt 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  han-
       dled 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

SunOS 5.10							    11 Apr 1991 						       datamsg(9F)