Pass-through verbs (application program implements)

Although VTAM® does not implement the following verbs, VTAM provides services that enable application programs to implement them. In some cases, the application program handles everything, and the data passes through VTAM. An example of this would be the LUW_IDENTIFIER. In other cases, the application program handles most things, but requires assistance from VTAM. For example, the application program handles the use of SECURITY_USER_ID and SECURITY_PROFILE in conversation security, but VTAM negotiates conversation security at the time of the BIND. Also, the application program handles SYNCPT and BACKOUT, but VTAM provides a function for that with APPCCMD CONTROL=REJECT and APPCCMD CONTROL=SETSESS and the handling of the PS headers.

GET_ATTRIBUTES

Returns information pertaining to the specified conversation.

Much of the information defined for GET_ATTRIBUTES can be found in the FMH-5 that is used to start a conversation. To obtain this function, the application program should save the pertinent information from the FMH-5 when it is received or built.

The types and location of information returned on GET_ATTRIBUTES are:

CONVERSATION_CORRELATOR
A unique value used to correlate conversations. It is available in the FMH-5.
CONVERSATION_GROUP_ID
The variable for returning the conversation group identifier. This value is returned to the application program on the RPL extension for the conversation winner on the APPCCMD CONTROL=ALLOC and APPCCMD CONTROL=RCVFMH5 macroinstructions.
CONVERSATION_STATE
The variable for returning the current conversation state of the specified conversation. The current conversation state is returned in the RPL extension for every conversation-based (APPCCMD) macroinstruction.
MODE_NAME
The mode name group used for a session supporting a conversation. It is a returned parameter on an RCVFMH5 macroinstruction. The initiating LU must save the mode name it has requested.
PARTNER_LU_NAME
The variable for returning the name of the LU at which the remote transaction program is located. This is a name by which a local LU knows the partner-LU for the purpose of allocating a conversation. For more details, refer to the description of the LUNAME operand of the APPCCMD CONTROL=ALLOC macroinstructions in the z/OS Communications Server: SNA Programmer's LU 6.2 Reference. This name is contained in the BIND and in the read-only copy of the RPL provided by the ATTN(FMH5) exit.
PARTNER_NETWORK_QUALIFIED_LU_NAME
The variable for returning the network-qualified name of the LU at which the remote transaction program is located. If the partner's network-qualified LU name is not known, a null value is returned. It can be obtained by using APPCCMD CONTROL=OPRCNTL, QUALIFY=DISPLAY. This name is also contained in the BIND.
SYNC_LEVEL
Indicates the synchronization level of the conversation, as defined by LU 6.2 architecture. It is available in the FMH-5.

GET_TP_PROPERTIES

Returns information pertaining to the transaction program that issues the verb.

The types and location of information returned on GET_TP_PROPERTIES are:

LUW_IDENTIFIER
A unique conversation identifier used for accounting and sync point purposes. It is available in the FMH-5.
OWN_FULLY_QUALIFIED_LU_NAME
The application program's unique network name, consisting of the network identifier, if applicable, and the application LU name. The application program can find the network identifier (if present) in the X'06' vector and the application LU name in the X'02' vector in the resource-information vector list. This list is available to the application program when the OPEN for the ACB of the application program completes. (See Vector lists for the details of the resource-information vector list.)
OWN_TP_INSTANCE
The variable for returning the system-generated identifier for this instance of the transaction program.
OWN_TP_NAME
The variable for returning the local application program's own transaction program name. This information is received in the ATTN(FMH5) and in data of the RCVFMH5 macroinstruction.
PROTECTED_LUW_IDENTIFIER
The variable for returning the logical unit of work (LUW) identifier used by the transaction program when it accesses protected resources. For VTAM LU 6.2, this is the same as the LUW identifier, which is in the data returned for the RCVFMH5 macroinstruction.
SECURITY_PROFILE
A profile used for conversation security purposes. It is available in the FMH-5, in an access security subfield.
SECURITY_USER_ID
A user identifier used for conversation-level security. It is available in a security access subfield in the FMH-5.

GET_TYPE

Returns the type of conversation (full-duplex basic or full-duplex mapped). This information is available in the FMH-5.

Note: GET_ATTRIBUTES, GET_TP_PROPERTIES, and GET_TYPE are not technically pass-through verbs because the application program does not issue a macroinstruction that is processed by VTAM. The information requested by the GET_ATTRIBUTES, GET_TP_PROPERTIES, and GET_TYPE verbs is conversation-level information (for example, the partner network-qualified LU name or whether the conversation is basic or mapped). To manage its transaction programs, the application program must maintain this information. VTAM does not maintain this type of information. The GET_ATTRIBUTES, GET_TP_PROPERTIES, and GET_TYPE verbs are listed here to show that the function of these verbs, although not supported by VTAM, can be achieved by the application program.

BACKOUT: Restore all protected resources to their status as of the previous synchronization point.
POST_ON_RECEIPT: Requests that the conversation be posted when data or other information is available.
PREPARE_FOR_SYNCPT: Causes protected resources associated with the conversation to be prepared to advance to the next synchronization point. Protected resources are those currently allocated to the transaction with a synchronization level of SYNCPT. As part of processing the PREPARE_FOR_SYNCPT verb, the LU flushes its send buffer for the conversation.
SET_SYNCPT_OPTIONS: Changes the options that affect the processing of the SYNCPT, BACKOUT, and PREPARE_FOR_SYNCPT verbs. The default options are in effect when the transaction program starts. The options set by this verb remain in use until the verb is issued again or the transaction program ends. The program is not required to specify any parameter having a value that it does not need to change.
SYNCPT: Advance all protected resources to the next synchronization point.