perl-modperl mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Paul B. Henson" <hen...@acm.org>
Subject Re: HTTP and MPM support
Date Mon, 28 Jan 2019 23:00:28 GMT
On 1/28/2019 1:53 PM, Mark Blackman wrote:
> 
> https://perldoc.perl.org/threads.html#WARNING  Threads are discouraged 
> in Perl these days

Yes, that is indeed what the documentation says; however, there is a far 
cry between "Perl is single-threaded by design and history and has no 
reliable support for threading" and "use of threads is discouraged in perl".

Looking back to the original discussion that led to that caveat 
https://www.nntp.perl.org/group/perl.perl5.porters/2014/03/msg213382.html 
a good summary of why it is there is:

"The patch came about because unmanaged expectations of support are 
causing social problems"

And further discussion about it 
https://www.perlmonks.org/?node_id=1107534 has a similar insight:

"that this particular formulation is just smoke and mirrors to repel 
'annoying newbies"

Then in this bug discussing the verbiage 
https://rt.perl.org/Public/Bug/Display.html?id=133021 a developer comments:

"The fact is that threads work, they are maintained, and they currently 
do not have any bugs preventing their use."

Basically, perl threads are heavyweight, not lightweight, and use of 
non-thread safe Perl code whether your own or in third-party modules 
will cause potentially nondeterministic problems. The warning is 
basically there to scare away people who don't have sufficient expertise 
to make it work and will likely come complain and ask for help with 
something the developers don't want to have to explain over and over again.

Back when I was running DCE/DFS and maintaining the perl modules on top 
of that, I used threaded perl heavily with no issues. As long as the 
mechanism of and caveats regarding Perl threads are understood, and 
there is a justifiable reason to be using them rather than some other 
construct, discouraged is not deprecated nor unavailable/unreliable.

Mime
View raw message