Author sdaoden
Recipients bobbyi, gregory.p.smith, neologix, nirai, pitrou, sdaoden, vstinner
Date 2011-05-17.10:35:24
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Message-id <20110517103517.GA82726@sherwood.local>
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@ Nir Aides wrote (2011-05-16 20:57+0200):
> Steffen, can you explain in layman's terms?

I am the layman here.
Charles-Fran├žois has written a patch for Python which contradicted
his own proposal from msg135079, but he seems to have tested a lot
so that he then was even able to prove that his own proposal was
correct.  His new patch does implement that with a nice
introductional note.

He has also noticed that the only really safe solution is to
simply disallow multi-threading in programs which fork().  And
this either-or is exactly the conclusion we have taken and
implemented in our C++ library - which is not an embeddable
programming language that needs to integrate nicely in whatever
environment it is thrown into, but "even replaces main()".
And i don't know any application which cannot be implemented
regardless of fork()-or-threads instead of fork()-and-threads.
(You *can* have fork()+exec()-and-threads at any time!)

So what i tried to say is that it is extremely error-prone and
resource intensive to try to implement anything that tries to
achieve both.  I.e. on Solaris they do have a forkall() and it
seems they have atfork handlers for everything (and even document
that in the system manual).  atfork handlers for everything!!
And for what?  To implement a standart which is obviously
brain-dead because it is *impossible* to handle it - as your link
has shown this is even confessed by members of the committee.

And writing memory in the child causes page-faults.
That's all i wanted to say.
(Writing this mail required more than 20 minutes, the mentioned
one was out in less than one.  And it is much more meaningful
Date User Action Args
2011-05-17 10:35:25sdaodensetrecipients: + sdaoden, gregory.p.smith, pitrou, vstinner, nirai, bobbyi, neologix
2011-05-17 10:35:25sdaodenlinkissue6721 messages
2011-05-17 10:35:24sdaodencreate