Re: How do I make the garbage collector throw an exception when it fails to auto-close a filehandle?

[ikegami]

When a function has special cleanup needs, use tilly's ReleaseAction.

use ReleaseAction qw( on_release );

sub something {
   ...

   open my $fh, ...

   my $closer = on_release {
      if (defined($fh) && defined(fileno($fh))) {
         close($fh)
            or die(...);
      }
   };

   ...
}

$closer holds a reference to $fh, so $closer will get destroyed before $fh. (Not necessarily true if they survive until global destruction.)

[Aristotle]

Yah, I’m aware of the concept. I would use it (more readily than a special IO class, possibly, although my opinion on that changes every other day), but for a single close $fh or die "Couldn't close: $!" statement it just doesn’t seem worthwhile. It’s maddening – it’s a simple single statement whose absence is not worth complicating the code for, but it’s still annoying to have to write it, and there’s so little missing to make it unnecessary…

[ikegami]

Nevermind. die in destrutor. Doesn't work.

use strict;
use warnings;

use ReleaseAction qw( on_release );

$| = 1;

sub something {
   my $closer = on_release {
      print "on_release enter\n";
      die("test");
      print "on_release exit\n";
   };
}

print "pre\n";
something();
print "post\n";

outputs

pre
on_release enter
        (in cleanup) test at script.pl line 11.
post

Tested on 5.6.1 & 5.8.8