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Re^2: FileHandles and threads

by zentara (Archbishop)
on Sep 22, 2005 at 18:21 UTC ( #494239=note: print w/replies, xml ) Need Help??


in reply to Re: FileHandles and threads
in thread FileHandles and threads

Thanks for that code example! Passing a filehandle through a thread shared variable was something I've been searching for for awhile. Just for demonstration purposes, it can go the other way too.....create the filehandle in the thread, and read it in main.
#!/usr/bin/perl use warnings; use strict; use threads; use threads::shared; my %shash; #share(%shash); #will work only for first level keys my %hash; share ($shash{'go'}); share ($shash{'fileno'}); share ($shash{'pid'}); share ($shash{'die'}); $shash{'go'} = 0; $shash{'fileno'} = -1; $shash{'pid'} = -1; $shash{'die'} = 0; $hash{'thread'} = threads->new(\&work); $shash{'go'} = 1; sleep 1; # cheap hack to allow thread to setup my $fileno = $shash{'fileno'}; open (my $fh, "<&=$fileno") or warn "$!\n"; while ( <$fh> ){ print "In main-> $_"; } #wait for keypress to keep main thread alive <>; # control-c to exit ################################################################## sub work{ $|++; while(1){ if($shash{'die'} == 1){ goto END }; if ( $shash{'go'} == 1 ){ my $pid = open(FH, "top -b |" ) or warn "$!\n"; my $fileno = fileno(FH); print "fileno->$fileno\n"; $shash{'fileno'} = $fileno; $shash{'go'} = 0; #turn off self before returning }else { sleep 1 } } END: } #####################################################################

I'm not really a human, but I play one on earth. flash japh

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Re^3: FileHandles and threads
by BrowserUk (Patriarch) on Sep 22, 2005 at 20:17 UTC

    I first played with this a couple of years ago. I first mentioned it here about a year ago in Re^3: Passing globs between threads.

    By using a pool of threads and passing the filenos via a queue, it is possible to efficiently emulate all the usual forms of forking server architecture.


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