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Re: Asynchronous callbacks from C

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Artur Bergman
July 5, 2001 06:12
Re: Asynchronous callbacks from C
Message ID:
01-07-05 15.04, skrev David M. Lloyd på följande:

> On Tue, 3 Jul 2001, Benjamin Stuhl wrote:
>>> I have written an XS interface into a library that performs I/O and
>>> then can asynchronously call a C function upon completion.  Is there a
>>> SAFE way I can reflect an asynchronous callback into Perl?
>> AFAIK, only if the perl is built to expect such. In 5.8.0-to-be there
>> is the PERL_ASYNC_CHECK which is used for safe signals. You would have
>> to hack around a bit in the core to interface that to your XS, and
>> even then it would only work with a perl built for it.
>> Maybe 5.8.0 should make PL_signal_pending or whatever it's called
>> public and provide a way for modules to register a event-checking
>> callback?
> I can't help but be jealous of PHP/Zend in this respect.  I have a friend
> who just wrote a signal handling *add-on* module (that is, there was no
> hacking required of the core engine) because he was able to use an API
> function to insert a C callback that is called between every opcode (or
> whatever they call them... I think they have a subtly different name for
> the same concept).
> It would be awesome to have something like that in Perl.  I guess that the
> performance hit associated with such a callback would be minimal... well
> worth the added power.
> - D

Like Benjamin said, we have PERL_ASYNC_CHECK that checks between opcodes,
this could added as a option to that.

How hard would it be for PERL_ASYNC_CHECK to call a C callback instead of a
perl signal handler? And if that C callback did call_sv()...


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