Using CONTROL=DEALLOC and CONTROL=DEALLOCQ

The application program initiates the abnormal deallocation by issuing one of the APPCCMD CONTROL=DEALLOC|DEALLOCQ macroinstructions. Processing of these macroinstructions causes the send buffer to be flushed and an FMH-7 and any error log data to be sent to the partner. The conversation is ended and enters FDX_RESET state.

Note: An FMH-7 and any error log data are not sent to the partner when the conversation is in RECEIVE-ONLY state.

There are four types of the APPCCMD CONTROL=DEALLOC and the APPCCMD CONTROL=DEALLOCQ macroinstructions that can be used to abnormally deallocate a full-duplex conversation:

QUALIFY=ABNDPROG
QUALIFY=ABNDSERV
QUALIFY=ABNDTIME
QUALIFY=ABNDUSER

Each of these types is described in the following section.

ABNDPROG: Specifies that an error makes it impossible to continue meaningful communication over the conversation. It is issued for errors detected by the processing threads in the application program that correspond to transaction programs. An example of this type of error could be the receipt of incorrect data on a CONTROL=RECEIVE macroinstruction. This type of error causes a sense code of X'08640000' to be generated in the FMH-7 used by VTAM® in processing the error. (See Sense codes for FMH-7 for a list of FMH-7 sense codes.)
ABNDSERV: Specifies that an LU services component has detected an error. This type of error occurs when the application program has implemented an LU 6.2 function in addition to that provided by VTAM. For example, an application program might implement mapped conversations. Errors relating to the application's implementation would be service errors. If the errors were serious enough to deallocate the conversation, the application program would issue this QUALIFY variation. This type of error causes a sense code of X'08640001' to be generated in the FMH-7 used by VTAM in processing the error. (See Sense codes for FMH-7 for a list of FMH-7 sense codes.)
ABNDTIME: Specifies that the application program has not received expected information within an application-determined length of time. This type of error causes a sense code of X'08640002' to be generated in the FMH-7 used by VTAM in processing the error. (See Sense codes for FMH-7 for a list of FMH-7 sense codes.) ABNDTIME can be used by the application program to handle errors originating on its side of the conversation or when it fails to receive information from a partner LU. Its primary intent is to handle timing errors on the local side of a conversation. For example, if an application program has been waiting for one of its transaction programs to send data, and the wait exceeds the time limit, it would use this type of deallocation to end the conversation.
ABNDUSER: Specifies that the application program is ending the conversation and provides VTAM with a user-specified sense code. The sense code must be valid for an FMH-7. The application program must ensure that it is valid. An example of the type of error this is used for would be the receipt of an FMH-5 with errors. (See Sense codes for FMH-7 for a list of FMH-7 sense codes.)

Refer to z/OS Communications Server: SNA Programmer's LU 6.2 Reference for details on the syntax and operands for these macroinstructions.