I'd also add that sharing data between threads tends to be nicer than messing with shared memory portably, mostly because Unix shared memory never really made sense to me.

Personally, I was never impressed with it on VMS. On Unix it's an absolute dream in comparison. (At least this is what my unreliable synapses are telling me.)

Shared memory is not perfect (what is, come to that), but it allowed me on one project, years ago, to share "live, up-to-date" data between users at twelve different sites, and did so in a reliable, relatively stable way. I've not done much with threading, so my view may be prejudiced, but you would have to prove to me that threading would be a better solution on such a situation. I'd listen, but I'd listen with a cynical ear.

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tbone1
Ain't enough 'O's in 'stoopid' to describe that guy.
- Dave "the King" Wilson