Details of filehandles

setuk has asked for the wisdom of the Perl Monks concerning the following question:

I am using POE - and its great.

Using it to fork children and have them communicate back with the parent process using POE::Filter::Reference.

In some instances i note that when the children throw STDERR messages or STDOUT messages they arent getting back to POE.

I also note this is nothing to do with POE since when i write STDERR outside of the POE call i also dont see that sent back.

So now im theorising that STDERR and STDOUT have been directed elsewhere. Im sure this is simple but how do i tell where a certain filehandle is set to send its output??

Comment on Details of filehandles

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Re: Details of filehandles by Joost (Canon) on Oct 28, 2009 at 00:06 UTC
Are you using POE::Wheel::Run or something else to set up the IO? P::W::Run has specific methods for catching stdout and stderr. As usual, it'll probably help if you can post some code that demonstrates the problem. Edit: the unix program `lsof` will list open filehandles for all processes, which may be useful. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re^2: Details of filehandles by setuk (Initiate) on Oct 28, 2009 at 10:21 UTC
I use P::W:R but then this calls subclasses that spawn interactive telnet sessions with remote devices. Im trying to identify at the point i try i send a message back where STDERR and STDOUT are pointed to as i think one of the subclasses has it. i'll see what i can come up with via lsof	[reply]
Re: Details of filehandles by moritz (Cardinal) on Oct 27, 2009 at 23:32 UTC
With -t you can test if a file handle is connected to a terminal (and thus not redirected). I don't know how you get more specific information out of it though. Perl 6 - links to (nearly) everything that is Perl 6.	[reply]