I meant a global Perl variable -- one that would persist in a persistent interpreter. Specifically, a "package variable" of this type:

   our %hash = ();

On 10/13/2016 04:26 PM, Daniel-Constantin Mierla wrote:


is it about a global variable defined inside the perl script or you mean
kamailio.cfg variables? The terminology you used might be clear for Perl
guys, but as I am not one, I want to clarify it...

As generic remarks -- kamailio is multi-process application, so each
child is a process, not a thread. Each process has its own private
memory space, so a global kamailio.cfg variable such as $var(x) is
defined in each process and each process has access to the one specific
to it. There are shared memory variables, like $shv(z) that all
processes can access and change, requiring synchronization to avoid races.


On 13/10/16 19:13, Alex Balashov wrote:

Given the presence of a global (e.g. "our") package variable in an
embedded Perl script used through app_perl, is there any implicit
thread safety?

That is to say, can a Perl function invoked by one SIP worker reset
the value of a global while another instance of the function invoked
by a different SIP worker is accessing it?

And if so, is it safe to use generic perlthr locking to avoid this?


-- Alex

Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 (direct) / +1-800-250-5920 (toll-free)
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