datamsg(9f) - osol9

1datamsg(9F)              Kernel Functions for Drivers              datamsg(9F)
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NAME

6       datamsg - test whether a message is a data message
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SYNOPSIS

9       #include <sys/stream.h>
10       #include <sys/ddi.h>
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14       int datamsg(unsigned char type);
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INTERFACE LEVEL

18       Architecture independent level 1 (DDI/DKI).
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PARAMETERS

21       type    The  type  of  message  to  be tested. The db_type field of the
22               datab(9S) structure contains the message type. This  field  may
23               be     accessed     through    the    message    block    using
24               mp->b_datap->db_type.
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DESCRIPTION

28       The datamsg() function tests the type of message to determine if it  is
29       a data message type (M_DATA, M_DELAY, M_PROTO , or M_PCPROTO).
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RETURN VALUES

32       datamsg returns
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34       1    if the message is a data message
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37       0    otherwise.
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CONTEXT

41       The  datamsg()  function  can be called from user, interrupt, or kernel
42       context.
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EXAMPLES

45       The put(9E) routine enqueues all data  messages  for  handling  by  the
46       srv(9E)  (service)  routine.  All  non-data messages are handled in the
47       put(9E) routine.
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49         1 xxxput(q, mp)
50         2      queue_t *q;
51         3      mblk_t *mp;
52         4 {
53         5    if (datamsg(mp->b_datap->db_type)) {
54         6            putq(q, mp);
55         7            return;
56         8    }
57         9    switch (mp->b_datap->db_type) {
58         10    case M_FLUSH:
59                          ...
60         11    }
61         12 }
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