From the point of view of ESL, once each configured session has been started by your emulation software, it can be in one of three states:
Disconnected
When disconnected, the session is not controlled by ESL. It may, however, currently be connected to another program.
Connected Not Active
When connected but not active, the session is controlled by ESL. However, it is not the session that is acted upon by the set of ECS subroutines that read, write, or send data. Other running programs are prevented from connecting to this session.
Connected and Active
When connected and active, the session is controlled by ESL and is acted upon by the set of ECS subroutines that read, write, or send data. Other running programs are prevented from connecting to this session.
At any given time, ESL can be connected to none, some, or all of the started 3270/5250 host sessions. If it is connected to one or more sessions, only one of these can be the active connected session; the rest, if any, are not active but remain connected. If there is no active connected session, an error condition will result from calling any ECS subroutine that reads, writes, or sends data, returns status information, and so on.
The ECS subroutines that connect to or disconnect from 3270/5250 host sessions are:
