Process flow during attention sequences

Attention events are handled by an attention sequence. Any of the following actions can trigger an attention event:

• The Database-Library issues a dbcancel( ) command.

• A SQL user cancels processing while the server is sending results.

• An APT program or form issues a closesql command.

When an attention sequence is issued, the process flow occurs as follows:

1. Open Client issues an attention packet to DirectConnect, then discards anything else received until it receives a TDSDONE packet with the attention Ack bit on.

2. DirectConnect converts the attention packet into a SNA SIGNAL command, issuing an LU 6.2 request-to-send verb. DirectConnect then discards any results received from the mainframe until receiving a TDS DONE packet with the attention Ack bit on.

3. At the mainframe, CICS receives the SIGNAL command and informs the Server Option.

4. Gateway-Library passes back a return code, indicating TDS_CANCEL_RECEIVED, on all subsequent TDSNDROW, TDSNDMSG, and TDSETPRM calls from an application. Any data associated with TDSNDROW or TDSNDMSG calls is discarded until the application issues a TDSNDDON call.

   For details on these calls, see the Mainframe Connect Server Option Programmer’s Reference for COBOL or PL/1.

5. When the application issues a TDSNDDON call, the Server Option support sends a TDS DONE packet with the attention Ack bit on. This ends the attention sequence.

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