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Important: The information in this document is obsolete and should not be used for new development.

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Inside Macintosh: Networking /
Chapter 6 - AppleTalk Transaction Protocol (ATP) / About ATP


ATP Flags

Many of the functions that you use for an ATP transaction pass control information in an ATP parameter block field called atpFlags. This field comprises a single byte whose bits you can set to signal control information, if appropriate. In some cases, ATP sets these flag bits for its own use. The discussion of each function that uses these flags includes the control information about the bits specific to that function. Table 6-1 shows the Pascal and assembly constants defined for these bits.
Table 6-1 Constants for ATP flag bits
BitPascal
constant
Assembly constantMeaning
0atpSendChkvaluesendChkUse DDP's checksum feature when sending a packet.
1atpTIDValidvaluetidValidThe transaction ID value that ATP assigns is set; you can check the reqTID field now.
2NoneatpXcallThis exactly-once transaction request uses an extended parameter block, the last field of which (TRelTime) is set to the release timer value for
the ATP responder side.
3atpSTSvalueatpSTSBitThe ATP requester must retransmit a request immediately. (ATP sets the send-transmission-
status bit, which it uses internally.)
4atpEOMvalueatpEOMBitThe last packet in this response is the end
of the message.
5atpXOvalueatpXOBitThis request is an exactly-once transaction.


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© Apple Computer, Inc.
7 JUL 1996