Manual Pages for UNIX Operating System command usage for man datamsg

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 (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  deter-
     mine  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;



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                          datamsg(9F)



       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 5.11          Last change: 16 Jan 2006                    2