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Re: Does perl really need to use sigsetjmp? (18% performance hit)

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From:
Alan Burlison
Date:
January 9, 2001 05:13
Subject:
Re: Does perl really need to use sigsetjmp? (18% performance hit)
Message ID:
3A5B0E75.3E79AE4A@uk.sun.com
Horsley Tom wrote:

> On most systems I know of, the guideline is what the name implies.
> If you want to longjmp out of a signal handler, you need to use the
> sig versions of the routines since there are signal frames and extra
> process state cleanups that have to happen.

Not so.  The only difference is whether the signal disposition is reset
or not.  In implementation terms, sigsetjmp is the same as setmmp except
for the addition of a getcontext() syscall, to get the current signal
mask etc.

Also, neither sigsetjmp nor setjmp are MT-safe - yet another reason why
the current perl threads implementation will always be unreliable.

Alan Burlison
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