Kernel Functions for Drivers                          datamsg(9F)



NAME
     datamsg - test whether a message is a data message

SYNOPSIS
     #include 
     #include 



     int datamsg(unsigned char type);


INTERFACE LEVEL
     Architecture independent level 1 (DI/DKI).

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


DESCRIPTION
     The datamsg() function tests the type of message  to  deter-
     mine  if it is a data message type (MDATA, MDELAY, MPROTO
     , or MPCPROTO).

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      queuet *q;
       3      mblkt *mp;
       4 {
       5    if (datamsg(mp->bdatap->dbtype)) {
       6            putq(q, mp);
       7            return;



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                          datamsg(9F)



       8    }
       9    switch (mp->bdatap->dbtype) {
       10    case MFLUSH:
                        ...
       11    }
       12 }


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


     Writing Device Drivers


     STREAMS Programming Guide







































SunOS 5.11          Last change: 16 Jan 2006                    2