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Date: Thu, 25 May 2006 12:24:13 +0400
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To: Sara Golemon <pollita@php.net>
CC: Michael B Allen <mba2000@ioplex.com>, internals@lists.php.net
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Subject: Re: [PHP-DEV] Re: Signals in Extensions
From: rasmus@lerdorf.com (Rasmus Lerdorf)

Sara Golemon wrote:
>> I have an extension that interfaces with a
>> library that sets a signal handler for some
>> common signals. In particular the library
>> forks processes and does socket writes
>> so it needs to be able to handle SIGCHLD
>> and SIGPIPE. It also registers some other
>> signals for debugging purposes. Can I
>> anticipate any kinds of problems from this?
>> Does the Zend engine use any signals in particular?
>>
> It's not PHP/Zend you should be afraid of... the interpreter goes a long way
> towards avoiding the use of signals because it's designed to run on
> <whatever> webserver and that webserver may or may not try to use signals in
> one way or another.  If you're using the CGI SAPI you might be safe, other
> than that.... Best of luck to ya.

Well, we do need SIGALRM for timeouts, but yes, beyond that we should be 
signal-clean.  But as Sara says, PHP is usually embedded inside 
something else and that something else tends to use signals for all 
sorts of stuff.

-Rasmus