For every conversation allocated, LU 6.2 API establishes and
maintains a set of flags or indicators that keep track of certain
control information necessary to manage the conversation. Whenever
an intrinsic is called, LU 6.2 API checks these flags before executing
the intrinsic to see if any information must be relayed to the TP.
The following flags are associated with each conversation:
Error flag.
The error flag is used to inform the TP that some type of error
has occurred.
RequestToSendReceived flag.
The RequestToSendReceived flag tells the TP whether a RequestToSend notification has been received from the remote
TP. A RequestToSend is the only control information that can be received
in the same intrinsic call with data.
State indicator. The state
indicator keeps track of the conversation state of the local TP.
If the state changes, the state indicator changes. When an intrinsic
is called, the state indicator is checked to ensure that the intrinsic
can be called from the current state.
Synchronization level indicator.
The synchronization level indicator records the synchronization
level that is established when a conversation is allocated. If an
intrinsic is called that can be executed only at a certain synchronization
level, the synchronization level indicator is checked to verify
that the conversation was allocated with the appropriate synchronization
level.
