Perl 5.8, sockets and binmode()

Jenda has asked for the wisdom of the Perl Monks concerning the following question:

I was notified that Mail::Sender (sending emails through SMTP via socket()s) doesn't work with Perl 5.8 with some SMTP servers if the script runs under Windows.

I tried to compile 5.8 myself (Win2k, perlio enabled) and used a TCP/IP sniffer to see what do I send to the server, and sure enough ... even though I do binmode($socket); the \x0D\x0A I send into the socket gets changed into 0D0D0A.

I tried to use binmode( $socket, ':raw:perlio') as well as binmode( $socket, ':raw'), but it did not change the results at all.

Adding

use open OUT => ':raw';
[download]

use open OUT => ':raw:perlio';
[download]

into the module did help though. Since I would like to be able to support 5.005, I cannot just add the use statement into the module, but

BEGIN {
    if ($] >= 5.008) {
        require 'open.pm';
        'open'->import(OUT=>":raw:perlio");
    }
}
[download]

seems to work fine.

I'm also using

binmode($s)
    unless ($] >= 5.008);
[download]

later though that's probably not necessary.

I don't like this solution though. Is there any other (better) way? What should I do?

Thanks, Jenda

Comment on Perl 5.8, sockets and binmode() Select or Download Code

Replies are listed 'Best First'.
Re: Perl 5.8, sockets and binmode() by Aristotle (Chancellor) on Nov 06, 2002 at 20:14 UTC
How about (untested!) something like this for clarity: `BEGIN { eval "require 5.008; use open OUT => ':raw:perlio'; sub _binmode() + {}"; eval "sub _binmode { binmode @_ }" if $@; }` [download] Then replace the `binmode` with `_binmode` and everything should happen automagically. The prototype will even cause these calls to be optimized away complete on Perls that don't need them. Makeshifts last the longest.	[reply] [d/l]
Re: Re: Perl 5.8, sockets and binmode() by Jenda (Abbot) on Nov 06, 2002 at 20:31 UTC
I guess I could redefine the binmode(). I can't use the `sub binmode () {}` though ... keep in mind that the procedure gets some parameters. So it can't be optimized away. It's a shame the $] is not treated as a constant. If it was then the `binmode(...) unless $] < 5.008` could be optimized away. Not that it matters. But the `use open ...` within the `eval ""` doesn't work. The `use open` pragma seems to be lexical if used this way. That's why am I using the require() and `'open'->import()`. Jenda	[reply] [d/l] [select]
Re^3: Perl 5.8, sockets and binmode() by Aristotle (Chancellor) on Nov 06, 2002 at 20:38 UTC
Ah, but you can retrofit that. `use constant PRE_5_8 => $[ < 5.008; binmode $fh if PRE_5_8;` [download] You can also use the constant for the `BEGIN` block if you are so inclined, of course (provided you define it before the block). Makeshifts last the longest.	[reply] [d/l]
Re: Perl 5.8, sockets and binmode() by RMGir (Prior) on Nov 07, 2002 at 14:25 UTC
Your fix (and the other suggestions here) all seem reasonable to me. This is a known problem, by the way, so it's already been fixed in the development branches. -- Mike	[reply]