I'm writing an application which needs a web interface, so I found the module Net::HTTPServer, which seemed to do its job nicely. However, when I first ran the example snippet from the module's documentation, it failed. I investigated it and found out that the module was failing when trying to create the socket:

$self->{SOCK} = new IO::Socket::INET(LocalPort=>$port,
                                     Proto=>"tcp",
                                     Listen=>10,
                                     Reuse=>1,
                                     Blocking=>0);
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Neither $! nor Win32::GetLastErorr could tell what happened. So I managed to find out that commenting the Blocking=>0, the socket would be created successfully. However, after doing this, it would fail in another subroutine:

######################################################################
+#########
#
# _nonblock - given a socket, make it non-blocking
#
######################################################################
+#########
sub _nonblock
{
    my $self = shift;
    my $socket = shift;
    #-----------------------------------------------------------------
+---------
    # Code copied from POE::Wheel::SocketFactory...
    # Win32 does things one way...
    #-----------------------------------------------------------------
+---------
    if ($^O eq "MSWin32")
    {
        ioctl( $socket, 0x80000000 | (4 << 16) | (ord('f') << 8) | 126
+, 1) ||
            croak("Can't make socket nonblocking (win32): $!");
        return;
    }

    #-----------------------------------------------------------------
+---------
    # And UNIX does them another
    #-----------------------------------------------------------------
+---------
    my $flags = fcntl($socket, F_GETFL, 0) ||
        croak("Can't get flags for socket: $!\n");
    fcntl($socket, F_SETFL, $flags | O_NONBLOCK) ||
        croak("Can't make socket nonblocking: $!\n");
}
[download]

Even if I tried setting $self->{SOCK}->blocking(0), it would still fail inside the _nonblock subroutine. Eventually, I tried transforming _nonblock() into a dummy subroutine, which just returns, and the example ran just fine: I could, finally, access the webserver from my browser. However, I wanted to know how do I make the sockets non-blocking on Win32 if I ever need to do it. Or if that's the right approach, why was it failing. Thanks in advance.