You can pass an agent to WEL_PROCESS_LAUNCHER.launch to get the output. it works fine for us. And the agent is called as the output arrives, possibly several times based on the setting `block_size'.
And we wrote a descendant of WEL_PROCESS_LAUNCHER where you can pass some input text when launching the process.

I would have to inspect all our usage of PROCESS to figure out whether a fully functional BASE_PROCESS would work for us. And it might be that we would have to do the job of PROCESS (create a thread etc.) to use BASE_PROCESS. All that just because PROCESS does not want to rely on the {PLATFORM}.is_thread_capable anymore, but rely on ECF instead. 
A lot of work for us, for something which has been working fine for us so far. Needless to say that we would prefer to see the issues that are blocking us (e.g. console on Windows 2008, agent objects in storable) to be addressed first.

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Eric Bezault