APPC Conversation Verbs

This section describes the APPC conversation verbs. The description of each verb provides:

• A definition of the verb.
• The structure defining the VCB used by the verb. The structure is contained in the WINAPPC.H file. The length of each VCB field is in bytes. Fields beginning with reserv (for example, reserv2) are reserved.
• The parameters (VCB fields) supplied to and returned by APPC. A description of each parameter is provided, along with its possible values and other information.
• The conversation state(s) in which the verb can be issued.
• The state(s) to which the conversation can change upon return from the verb. Conditions that do not cause a state change are not noted. For example, parameter checks and state checks do not cause a state change.
• Additional information describing the verb.

Mapped conversation verbs are preceded by an MC_ designator. For example, the mapped conversation verb MC_ALLOCATE corresponds to the basic conversation verb ALLOCATE.

Most parameters supplied to and returned by APPC are hexadecimal values. To simplify coding, these values are represented by meaningful symbolic constants, which are established by #define statements in the WINAPPC.H header file. For example, the opcode (operation code) member of the mc_send_data structure used by the MC_SEND_DATA verb is the hexadecimal value represented by the symbolic constant AP_M_SEND_DATA. Use only the symbolic constants when writing TPs.