NetBatch Management Programming Manual

SPI Programming Considerations for the NetBatch

Subsystem

NetBatch Management Programming Manual—522462-003

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Retrieving and Decoding Event Messages

For detailed information on event-message retrieval and decoding, and for examples of

event-message retrieval in the C, COBOL, TACL, and TAL languages, see the EMS

Manual.

To retrieve and decode event messages from the NetBatch subsystem:

1. Declare a buffer of appropriate size for the EMS GETEVENT command and its

response. For recommended buffer sizes, see the EMS Manual.

2. Start an EMS consumer distributor and open it specifying the #ZSPI qualifier in the

process name.

3. Perform these tasks:

a. Format an EMS distributor CONTROL programmatic command to load a filter

you have written and to specify the source and destination of event messages,

if desired. (You use filters to select the event messages you want your

application to process. Filters are discussed further at the end of this section.)

b. Send the CONTROL command to the consumer distributor, using the

mechanism applicable to your programming language (for example, Guardian

procedure WRITEREADX for C and TAL, the READ verb for COBOL, or the

#REQUESTER built-in function for the TACL program).

4. Read the response from the distributor, using the mechanism applicable to your

programming language.

5. For each event message:

a. Format and send a GETEVENT command to the consumer distributor to get

the next event message, using the mechanism applicable to your programming

language.

b. Read the response from the distributor, using the mechanism applicable to

your programming language.

c. Call procedure SSMOVE or SSMOVETKN to move the context token from the

response buffer into the GETEVENT command buffer. The context token will

be required later, when your application resends the command to get the next

event message.

d. Call procedure SSGET or SSGETTKN to retrieve the token containing the

event message (ZEMS-TKN-EVENT) from the response buffer.

e. Call procedure EMSGET or EMSGETTKN to retrieve the subsystem ID (ZSPI-

TKN-SSID) and the event number (ZEMS-TKN-EVENTNUMBER) from the

event message. Together, these two tokens identify the event message and

determine what information tokens it contains.

f. Call procedure EMSGET or EMSGETTKN twice to retrieve the subject of the

event message. In the first call, retrieve the subject-mark token (ZEMS-TKN-