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Re: Non-blocking IPC to and from multiple children

by bbfu (Curate)
on Mar 29, 2004 at 15:33 UTC ( #340639=note: print w/replies, xml ) Need Help??


in reply to Non-blocking IPC to and from multiple children

I would use pipes instead of socketpairs, but mostly because I'm not really familiar with socketpairs.

The following code doesn't work on Win32, since select is (properly) implemented only for sockets on Win32. Presumably, you could use the same basic idea but with socketpairs and have it work on Win32 as well. *shrug*

#!/usr/bin/perl use warnings; use strict; use IO::Handle; use IO::Pipe; use IO::Select; my $stdout = IO::Pipe->new(); my $stdin = IO::Pipe->new(); defined(my $pid = fork) or die "Fork failed\n"; if($pid) { $stdout->reader(); $stdin ->writer(); $stdin ->autoflush(1); my $select = IO::Select->new($stdout); foreach my $key (@ARGV) { $stdin->print("parent ($$) send [$key]\n"); next unless $select->can_read(1); $stdout->sysread(my $buf, 1024); chomp($buf); print "parent ($$) recv [$buf]\n"; } $stdin->close(); waitpid($pid, 0); } else { $stdout->writer(); $stdin ->reader(); $stdout->autoflush(1); open STDOUT, ">&", $stdout; open STDIN, "<&", $stdin; exec "$^X", "tst.pl"; }

And tst.pl:

#!/usr/bin/perl use warnings; use strict; $|++; while(<STDIN>) { chomp; next unless /\[(\d+)\]/ && $1 % 2 == 1; # Only odds print "$1 is odd\n"; }

bbfu
Black flowers blossom
Fearless on my breath

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[Discipulus]: Corion are you would able to realize such thing? O_O
[Corion]: In the same vein I have a script that automates Firefox to enter some data into another system. It's not faster than the people using the script if they were to do it manually, but they prefer not having to check the data and not having typos when ...
[Corion]: ... entering the data
[Corion]: Discipulus: I don't know whether I could really do that, but the init process itself mostly launches other processes, and the whole startup is just following a path of dependencies and making sure they are all running. Which basically is what ...
[Discipulus]: when at work my time is (temporarly) owned by the firm, so i do not care (coworkers whatch movies.. I code Perl)
[Corion]: ... make already does, except for files instead of programs. But maybe with some /proc hackery, that could be eliminated and one could use plain make :-D
[choroba]: systemd just makes is asynchronous
[choroba]: so, make -j
[Corion]: Discipulus: Yeah - but when writing Perl to save time (instead of having fun), it helps to look whether you're actually saving time ;) Why spend 5 minutes doing manually what you can spend three years automating? ;)
[Corion]: choroba: Oh, yeah :-D

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