Re: thred's pids

At 11:08 AM +0200 11/4/04, Mihai Vlad wrote:
>David Greaves wrote:
>>Mihai Vlad wrote:
>>>none of these return the actupa pid of the thread:( (or at least i 
>>>can't interpret it)
>>>
>>>here-s what i get:
>>>
>>>threads=SCALAR(0x81733b4)=SCALAR(0x8173390)
>>>135846736
>>>1
>>>
>>>when these threds were running ps ax gave me these:
>>>25234 pts/4    S+     0:00 /usr/bin/perl ./test
>>>25235 pts/4    S+     0:00 /usr/bin/perl ./test
>>>25236 pts/4    S+     0:00 /usr/bin/perl ./test
>>>
>>>I'm interested in the number 25236 wich i'm sure is the pid to my 
>>>opened thred , how can i get this number just using perl and it's 
>>>modules? :( i've tryied like anything.... now i'm trying to see 
>>>the code in how a thread is created perhaps there is something 
>>>there, if you know already or know a better way pls tell me.
>>>10x
>>
>>
>>OK
>>That's what I expect. The tid of your thread ($thr1) is 1.
>>
>>25235 that's beyond my knowledge level :)
>>
>>From reading the docs, I'm pretty sure that you're not supposed to 
>>look at it - it's implementation specific.
>>I'd expect some systems not to have a per-thread OS-level pid - 
>>indeed linux may not in the future.
>>
>>Why do you need to?
>>
>>Are you wanting to use signals? In which case set the signal 
>>handler in the thread and signal() the master PID.
>>See if that works.
>>I'd expect it to be threadsafe given the docs caveat:
>>If your Perl has been built with PERL_OLD_SIGNALS (one has to 
>>explicitly add that symbol to ccflags, see |perl -V|), signal 
>>handling is not threadsafe.
>>
>>David
>>
>>
>No, i have a test script written in perl, that starts over 1000 threads

With regards to resource usage of 1000 threads, you might want to 
check my article about that on Perl Monks:

   http://perlmonks.org/index.pl?node_id=288022


>  that read/write on a specific socket , every thread logs it's 
>actions on a single file called threadTID.log. Sometimes some of the 
>threads don't close (the script is safely made: i mean no write or 
>read is left unlogged or unsupervised, if a single write failes the 
>thread is killed) so i'm suspecting that the program i'm testing is 
>to blame for.
>Now it would be very easy to identify the logs of the hanging 
>threads if they would be something like thrPID.log.
>
>Of course i've implemented a more simple solution like: writing 
>something at the end of a log when the thread closes:P and by this 
>way making it easy for my to identify the remaining threads logs.
>But i was curious if i could find the threads pid and implemente 
>like i've written above for future knolledge, and scripts:). I know 
>that threads written in C and other languages know their pids, so 
>i'm really curious if i can find this in perl...
>
>Regarding the signals i am aware of the %SIG hash.

 From the documentation of my Thread::Signal module on CPAN:

   http://search.cpan.org/~elizabeth/Thread-Signal-1.11/lib/Thread/Signal.pm


=====================================================================
SYSTEMS IT DOESN'T WORK ON

Check the output of:
   perl -V:cppflags

The absence of the string -DTHREADS_HAVE_PIDS is a good indication 
that Thread::Signal will most certainly not work. However, if that 
string does occur, it is no guarantee that Thread::Signal will work. 
The only way to find out is to run the test-suite and see whether 
that works.
=====================================================================

You might also want to check the Caveats section.



Liz