perlvar should mention STDIN, STDOUT, STDERR #13090

p5pRT · 2013-07-08T02:08:08Z

Migrated from rt.perl.org#118797 (status was 'open')

Searchable as RT118797$

p5pRT · 2013-07-08T02:08:09Z

From @rjbs

Created by @rjbs

perlvar.pod documents ARGV and ARGVOUT but not STDOUT, STDIN, and STDERR,
nor DATA.

Even if only by cross-reference, these should be documented in perlvar.

Perl Info


Flags:
    category=docs
    severity=wishlist

Site configuration information for perl 5.19.1:

Configured by rjbs at Thu Jun 20 21:56:11 EDT 2013.

Summary of my perl5 (revision 5 version 19 subversion 1) configuration:
   
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Locally applied patches:
    


@INC for perl 5.19.1:
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p5pRT · 2013-07-08T13:47:10Z

From @ikegami

On Sun, Jul 7, 2013 at 10:08 PM, Ricardo SIGNES
<perlbug-followup@perl.org>wrote:

# New Ticket Created by Ricardo SIGNES
# Please include the string: [perl #118797]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=118797 >

This is a bug report for perl from rjbs@cpan.org,
generated with the help of perlbug 1.39 running under perl 5.19.1.

-----------------------------------------------------------------
[Please describe your issue here]

perlvar.pod documents ARGV and ARGVOUT but not STDOUT, STDIN, and STDERR,
nor DATA.

Even if only by cross-reference, these should be documented in perlvar.

I tried to refer someone asking about @ISA to perlvar, but it wasn't
listed! Is it because it's a per-package variable? If so, the same argument
applies to DATA. I'd rather see both listed.

p5pRT · 2013-07-08T13:47:11Z

The RT System itself - Status changed from 'new' to 'open'

p5pRT · 2013-07-08T14:04:51Z

From @rjbs

Yes, if nothing else, an entry for @ISA that cross-references would be welcome.

p5pRT · 2013-07-16T23:31:44Z

From @kentfredric

That might also be a good place to note that STD{IN,OUT,ERR} are
"process global", ie: shared by all threads, which include Win32
Emulated Forks.

p5pRT · 2013-07-17T14:30:15Z

From @ikegami

On Tue, Jul 16, 2013 at 7:31 PM, Kent Fredric via RT <
perlbug-followup@perl.org> wrote:

That might also be a good place to note that STD{IN,OUT,ERR} are
"process global", ie: shared by all threads, which include Win32
Emulated Forks.

Interesting.

use strict;
use warnings;
use threads;
open FILE, '>', "$0.1.txt" or die $!;
async {
open FILE, '>', "$0.2.txt" or die $!;
print FILE "abc\n";
}->join();
print FILE "def\n";

Output:

perl a.pl
type a.pl.1.txt
def
type a.pl.2.txt
abc

With every instance of FILE changed to STDOUT:

perl a.pl
type a.pl.1.txt
type a.pl.2.txt
abc
def

p5pRT · 2013-07-20T00:26:47Z

From @kentfredric

Yeah, in my experience, this was the most surprising part of win32 IO
redirection.

You think because you can redirect IO on unix, and you can do it on
windows, that other things might work, for example, the common fork,
redirect, exec idiom.

But this little detail is the basic reason it doesn't work, and this is
why if you want to do non-blocking interactive IPC with a slave process
on Windows, most the things you'll try to use to solve that problem
won't work. ( The majority of modules that try handle this on windows
block until the slave terminates, and then map the handles back
afterwards ).

The only way I know of that lets you handle this on Win32 in real time
is this little known gem, which I try to spread awareness of where it
seems possible to do so:

https://metacpan.org/module/Win32::Job

use Win32::Job;
my $job = Win32::Job->new();
$job->spawn($execpath, $stringifed_arglist, {
stdin => $handle_for_inputstream,
stdout => $handle_for_outputstream,
stderr => $handle_for_stderrstream
});

And my testing demonstrates you can also do

$job->spawn($execpath, $stringifed_arglist, {
stdin => $handle_for_inputstream,
stdout => $foo,
stderr => $foo
});

And the behaviour will be as expected ( try doing that without
win32::Job ;) )

p5pRT added Wishlist affects-5.19 distro-darwin documentation labels Oct 19, 2019

xenu removed the affects-5.19 label Nov 19, 2021

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perlvar should mention STDIN, STDOUT, STDERR #13090

perlvar should mention STDIN, STDOUT, STDERR #13090

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

p5pRT commented Jul 16, 2013

p5pRT commented Jul 17, 2013

p5pRT commented Jul 20, 2013

perlvar should mention STDIN, STDOUT, STDERR #13090

perlvar should mention STDIN, STDOUT, STDERR #13090

Comments

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

From @rjbs

Created by @rjbs

p5pRT commented Jul 8, 2013

From @ikegami

p5pRT commented Jul 8, 2013

p5pRT commented Jul 8, 2013

From @rjbs

p5pRT commented Jul 16, 2013

From @kentfredric

p5pRT commented Jul 17, 2013

From @ikegami

p5pRT commented Jul 20, 2013

From @kentfredric