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Message-ID: <514344C4.4070908@gmail.com>
Date: Fri, 15 Mar 2013 15:56:52 +0000
From: Matej Kosik <5764c029b688c1c0d24a2e97cd764f@gmail.com>
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To: caml-list@inria.fr
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Subject: Re: [Caml-list] signal-unsafety of %!

On 15/03/13 14:36, oliver wrote:
> On Fri, Mar 15, 2013 at 02:30:29PM +0000, Matej Kosik wrote:
>> Hi,
>>
>> When I compile the attached program
>>
>>   (with compilers available directly from Debian's repositories)
>>
>> I can observe a (non-deterministic) deadlock.
>>
>> When I remove
>>
>> 	%!
>>
>> from the printf function inside the SIGALRM's handler, the deadlock never seem to occur.
>>
>> Obviously, interference can be easily introduced in concurrent programs; I was just surprised that even something like
> [...]
> 
> 
> Whats going on today?
> 
> Use Unix.sigprocmask.
> 
> Ciao,
>    Oliver
> 

Right, printf simply isn't reentrant.

(what I was observing was a program that was busy-looping, but stuck. I guess because internal shared data might have been damaged.).