perl IPC:Open3 minimal to pass perlcritic?
ipcopen3, perl, perl-critic
Solution
The error parameter to `IPC::Open3::open3` should not be undefined. The synopsis for `IPC::Open3` uses the `Symbol::gensym` function to pre-initialize the error argument:
my($wtr, $rdr, $err);
use Symbol 'gensym';
$err = gensym;
$pid = open3($wtr, $rdr, $err, 'some cmd and args', 'optarg', ...);
The input and output parameters can be replaced with autogenerated filehandles, so it is OK to pass `undef` for those arguments.
Of course the least verbose option to satisfy perlcritic here is
my @o = `ls 2>/dev/null` ## no critic
Problem
I am reading the perlcritic documentation to avoid backticks and use IPC::Open3 here: http://perl-critic.stacka.to/pod/Perl/Critic/Policy/InputOutput/ProhibitBacktickOperators.html I am trying to find the least verbose option that will work and satisfy perlcritic: ``` #!/usr/bin/perl use strict; use warnings; use IPC::Open3 'open3'; $SIG{CHLD} = 'IGNORE'; my $cmd = 'ls'; my ($w,$r,$e); open3($w,$r,$e,$cmd); my @o = <$r>; my @e = <$e>; 1; ``` But it complains with the following error: ``` Use of uninitialized value in <HANDLE> at ipc_open3.pl line 7 ``` Any ideas? EDITED: Ok, here is what I've got. Unless there is a way to simplify it, I'll stick to this: ``` #!/usr/bin/perl use strict; use warnings; use IPC::Open3 'open3'; $SIG{CHLD} = 'IGNORE'; use Symbol 'gensym'; my $cmd = 'ls'; my ($w,$r,$e) = (undef,undef,gensym); my $p = open3($w,$r,$e,$cmd); my @o = <$r>; my @e = <$e>; 1; ```