(on WinXP, AS 5.8.6)

I'm trying to come up with a generic way to pass filehandles between threads (wo/ having a priori knowledge of the filehandle's modes/layers). The only way I know of is to pass the fileno, and re-open in the receiving thread using open(FH, "&$fileno").

2 questions:

1) How can I get the open()'d modes for a filehandle on Win32 ? fcntl() doesn't work there, and I can't seem to find a Win32 module to do it...

2) I need to be able to re-apply the access modes and PerlIO layers in the recving thread. I can get the layers via PerlIO::get_layers(), and (hopefully) I can get the modes via a Win32 call (or via fcntl() everywhere else).

However, when I try to apply layers to a fileno open(), Perl barks in 2 arg open(), and creates a new file in 3 arg open(). 

use PerlIO;

my $fd;
open($fd, '+>>:raw', 'somefile.data') || die $!;

my $layers = ':' . join(':', PerlIO::get_layers($fd));

print "$layers\n";
#
# this creates a new file named "&3"
#
my $fn = fileno($fd);
my $fd2;
open($fd2, '+>>' . $layers, '&' . $fn) || die $!;
#
# this dies with "Invalid argument at filemode.pl line ..."
#
my $fd3;
open($fd3, '+>>' . $layers . ' &' . $fn) || die $!;

close $fd;
close $fd2;
close $fd3;

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Is there any way around this problem ?

In reply to Can't open($newfh, $mode_layers, '&' . fileno($fh)) by renodino

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