And how do you protect a caller from having to wait for the lock?
You don't. If they have to wait, then they wait.
You'd need a lock count here, where you can only change the
credentials when the count is zero. But when will that ever be?
It depends... for most non-threaded applications, immediately... for
threaded applications with lots of (day) disk IO, it could be
indefinite.
And btw, the count bumping/downing does cost.
Almost immeasurable. [sg]et[eu]id doesn't get called that often.
--cw
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