| Subject: | Tk::fileevent problem with IO::Socket on HP-UX |
I recently upgraded from Tk-800.023 to Tk-800.024.
I'm using perl 5.6.0 on HP-UX:
mholland@bmdke3 $ uname -a
HP-UX bmdke3 B.10.20 A 9000/778 2014451196 two-user license
mholland@bmdke3 $ perl -v
This is perl, v5.6.0 built for 9000/777-hpux
The upgrade broke one of my scripts where I've used
Tk::fileevent for handling response messages over an
IO::Socket::INET connection. While I got the fileevent
callback in 800.023, I didn't get it in 800.024.
However, when using plain files or anonymous pipes,
everything works fine, only IO::Socket seems to cause
this problem.
The behaviour can easily be reproduced with the following
code snippet:
-------------8<----------------------------------------------------------
use IO::Socket;
use Tk;
$d = pack( "n*", 42, 4711, 1234, 65535 );
$w = new MainWindow;
$s = new IO::Socket::INET 'localhost:'.(getservbyname('echo', 'udp'))[2]
or die "Cannot open socket for UDP echo: $!\n";
$w->fileevent( $s, 'readable', sub { $s->read( $res, length $d ) } );
$s->print($d);
$SIG{ALRM} = sub { $res = '' };
alarm 5;
DoOneEvent( Tk::DONT_WAIT ) until defined $res;
print $res eq $d ? "SUCCEED\n" : "FAIL\n";
-------------8<----------------------------------------------------------
I've tried to understand what could cause the problem by
looking at the code diffs between 800.023 and 800.024. The
only change related to Tk::fileevent was the introduction
of the untied filehandle in Event/Event.xs.
Looking at the differences between filePtr->io and tmpio,
I noticed that the xio_flags were different. While the
original filehandle filePtr->io had the IOf_FLUSH flag
set, xio_flags was zero for tmpio.
I simply added a line to also copy the flags...
IoFLAGS(tmpio) = IoFLAGS(filePtr->io);
...and everything works again, not breaking any tests.
As I don't fully understand what's going on behind the
scenes, this patch might just be some kind of kludge...
-- Marcus
diff -ruN Tk800.024/Event/Event.xs Tk800.024work/Event/Event.xs
--- Tk800.024/Event/Event.xs Mon Jan 7 10:35:44 2002
+++ Tk800.024work/Event/Event.xs Tue Sep 24 07:39:17 2002
@@ -344,6 +344,7 @@
IO *tmpio = GvIOp(filePtr->untied);
IoIFP(tmpio) = IoIFP(filePtr->io);
IoOFP(tmpio) = IoOFP(filePtr->io);
+ IoFLAGS(tmpio) = IoFLAGS(filePtr->io);
return newRV((SV *) filePtr->untied);
}
return &PL_sv_undef;