[Moscow.pm] STDIN <> и чёрная магия

[Dmitry Karasik]

да нуу все ж тупо:

close STDIN;
open FOO, '<', $0 or die;
print readline;

читает из 0 а должен из STDIN, вот и все

/dk


On Fri, Dec 09, 2011 at 04:17:29PM +0400, Mons Anderson wrote:
> Хз, вроде до moscow.pm должно было дойти
> 
> The problem is not in closing fd 0
> 
> Let's look at the following sample:
> 
> # dup.pl
> open my $fh, '<&=',0 or die;
> print fileno STDIN, ":", scalar readline STDIN;
> close STDIN;
> print fileno $fh, ":", scalar readline $fh;
> 
> ########
> bash $ { echo 1; sleep 1; echo 2; } | perl dup.pl
> 0:1
> 0:2
> 
> (During this I've investigated, that if we do echo -ne "1\n2\n" | perl dup.pl, then <$fh> receive nothing. I think that's because of buffered read. Don't know should be this considered a bug)
> 
> Then we add the same
> 
> open my $fh, '<&=',0 or die;
> 
> to the beginning of the example and check the fileno at the end
> 
> 0 == fileno $fh or die "fileno fh nonzero";
> 
> then we will see, that fileno 0 was kept, it still assigned to stdin (this could be checked additionally), but the behavior of this program still the same: we got an output of PerlIO.pm
> 
> On 09.12.2011, at 16:04, Dmitry Karasik wrote:
> 
> > On Fri, Dec 09, 2011 at 03:59:44PM +0400, Mons Anderson wrote:
> >> 
> >> On 09.12.2011, at 15:50, Dmitry Karasik wrote:
> >> 
> >>> нашел, все ясно:
> >>> 
> >>> 1: open( STDIN, '<', \$data ) делает 'require PerlIO::scalar' - т.е. находит этот PerlIO/scalar.pm и читает его черед fd(0). Ну
> >>> читает и слава богу.
> >> 
> >> Фиг. В моем примере, когда мы не даем закрыть fd 0 такого не происходило-бы.
> >> А все равно происходит.
> > 
> > в каком примере? и потом, там вполне может быть implicit close
> > 
> > -- 
> > Sincerely,
> > 	Dmitry Karasik
> > 
> > -- 
> > Moscow.pm mailing list
> > moscow-pm на pm.org | http://moscow.pm.org
> 

> -- 
> Moscow.pm mailing list
> moscow-pm на pm.org | http://moscow.pm.org


-- 
Sincerely,
	Dmitry Karasik