[rt.cpan.org #53264] Memory leak in _SetStdHandle() in child process

[Aldo Calpini via RT]

Mon Jan 04 04:09:17 2010: Request 53264 was acted upon.
Transaction: Correspondence added by ACALPINI
       Queue: Win32-Console
     Subject: Memory leak in _SetStdHandle() in child process
   Broken in: (no value)
    Severity: Critical
       Owner: Nobody
  Requestors: rcap...@cpan.org
      Status: new
 Ticket <URL: https://rt.cpan.org/Ticket/Display.html?id=53264 >


1) _SetStdHandle is an internal, undocumented method and should not be used
directly.
2) the leak is not in _SetStdHandle, which is a pure wrapper around the Win32
API of the same name. it is instead in the STD_INPUT_HANDLE() constant call.

the same behaviour can be observed with constants from other modules:

#!perl

use warnings;
use strict;

use Win32::File;
use Win32API::File qw(FdGetOsFHandle);

TRY: while (1) {
my $pid = fork();

# fork() failed.
next TRY unless defined $pid;

# Parent.
if ($pid) {
# Wait for child.
waitpid($pid, 0);
next TRY;
}

# Child.
print READONLY();
exit(0);
}

I don't know if this is due to the XS constant wrapper, or AUTOLOAD, or what
else, but for sure there's something wrong somewhere.

as a workaround, use:

my $std_input_handle = STD_INPUT_HANDLE();

before the loop, and use $std_input_handle in the child code.

cheers,
Aldo