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Easier to do it the other way: when you fork, keep the parent as the snapshot and keep going in the child. That way you can back up by terminating and resuming in the parent. I think this is what timetravelpdb does for Python: https://github.com/TomOnTime/timetravelpdb

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Yeah, thanks it was my first idea, but then 1) I'd have to re-attach everything to the child process and 2) I'd have to go one step further for every snapshot, right ? If everything goes well and I want to continue, next snapshot I'll have to fork the child process, and so on, no? The idea is to keep a somewhat short (some minutes?) of snapshots.

Thanks for the timetravelpdb link!

Here's another implementation of what's described above, it forks on each invocation of readline to provide undo for interactive interpreters. https://github.com/thomasballinger/rlundo

OK I love this, and not just because of the calls to system(nc) :-)

Your code made me think, maybe I'm tying myself into knots... But my thing is making hundred thousands of checkpoints so I'd have to have as many forks as savespoints. No way to coalesce parents, maybe reparenting could work there...

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