The Extract_TP_Name call (function name cmetpn) returns the TP_name characteristic.
CM_ENTRY Extract_TP_Name(
unsigned char FAR *conversation_ID,
unsigned char FAR *TP_name,
CM_INT32 FAR *TP_name_length,
CM_INT32 FAR *return_code
);
The conversation can be in any state except RESET.
There is no state change.
For an invoking program, the TP_name characteristic is the value in the side information referenced in the sym_dest_name parameter of the Initialize_Conversation call. For an invokable program, it is the name specified in the conversation startup request (which will have been matched with a name specified locally or in a Specify_Local_TP_Name call), and will therefore be the same as the TP_name characteristic of the partner program.
The name returned can be up to 64 bytes in length.