Description of the new feature/enhancement

On POSIX systems the master end will receive an EOF when all processes that use the slave have terminated or closed the connection. With ConPTY this does not appear to happen, as the pty handling process continues running (and could be used to start new processes). Closing the ConPTY will generate an EOF, but also terminate any remaining processes and possibly lose pending output.

Currently a master that does a blocking read from a ConPTY pipe will hang indefinitely when all slaves have terminated.

Proposed technical implementation details (optional)

Suggestion:

Add an API call to check whether a ConPTY is idle and has no active clients or pending data, and thus is safe to close, or in the alternative add an API call to ask the ConPTY to terminate as soon as its client count reaches zero and not output is pending.