Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:
Hi,
I've a doubt on accesssing one perl subroutine by multiple threads.
Let us say two threads (using perlcall APIs) access a perl sub named X.
First thread invoked X. while processing, First thread is preempted and
the Second thread starts executing and accessing the same sub X.
My question is, if the First thread continue execution from where it was
preempted by the Second thread?. Is perl subroutine thread safe.
We are getting some strange results.
If you have answers for the same please let us know. Please
contact me at poorna@india.hp.com
Thanks,
Poornachandran SM.
(tye)Re: Accessing one perl sub by multiple threads..
by tye (Sage) on Dec 07, 2000 at 22:52 UTC
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Perl isn't thread safe. You'll need to do one of the
following:
- Use some sort of mutex to prevent simultaneous
access to the Perl interpreter, making a "critical section"
that only one thread can use at a time. I believe someone
has already built this so you might be able to find it.
- Create (a pool of) separate Perl interpreters for
each thread that needs to call a Perl subroutines. This
won't work for you if the subroutines need to act on shared
data. Note that you can use the same Perl interpreter in
different threads so long as the Perl interpreter is
not built with threading support and only one thread
uses that interpreter at a time.
- Try embedding a Perl interpreter built with one
of the several experimental methods for supporting multiple
thread per interpreter and access the interpreter as
required by that method. This will cause the interpreter
to use mutexes to make critical sections around smaller
chunks of code. But none of these work 100% reliably so
you'll have to deal with that.
There might be some other methods, but the above should
give you a feel for what is required.
Please contact me at poorna@india.hp.com
Sorry, you'll have to check back here.
-
tye
(but my friends call me "Tye")
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Re: Accessing one perl sub by multiple threads..
by AgentM (Curate) on Dec 07, 2000 at 23:34 UTC
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| [reply] |