I agree on the concerns only partially. Maybe an assembler programmer used to suspect of all those "high-level" languages, but today assembler is used only in a restricted portion of programmers world. What I mean is that I'm looking for some facility to portably handle my issue, which can of course be quite different from what I've coded above. To put it in another way, I'd like some way to factor out all the needs that a suspend-and-resume approach would have, in order to simplify the task the next time. Until then, I agree that it's something that I have to deal with with extreme care.

I'm mostly a Linux guy, so the TSTP/CONT signaling would be fine most of the time. But sometimes my programs are used by less evolved guys, bound to use some legacy OS, which forces me to use it on that OS occasionally. The bottom line is that I was looking for something portable.

Checkpointing would help here to save state at intermediate steps, of course. I consider this a nice side effect :)