Re: IO::Select vs sysread(STDIN)

[jjore]

I can't speak with authority since (a) I haven't tried it and (b) I've 
never used select that way before. Still, it bothers me that you do all 
those fdopen() calls to the same typeglob. Can't you apply singleton to 
your STDIN IO::Handle so that you aren't getting duplicates? I would start 
there and then if that didn't work go looking for bugs.

Josh




Jim Cromie <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
04/25/2002 01:03 PM

 
        To:     [EMAIL PROTECTED]
        cc: 
        Subject:        IO::Select vs sysread(STDIN)


Folks,

Ive got code working on 5.6.1 on Linux that doesnt on ActivePerl build 
631 on win2000

My best guess (WAG at this point) is some interference between IO::Select,
which is the core of a messaging hub, and STDIN, which Im trying to use 
to annotate
the message logs as theyre written.

problem arises when user gives option -anote, which ends up in %$opt 
passed into Log::new(),
causing ctor to open an IO::Handle on STDIN.  This appears to break the 
IO::Select operations,
which would otherwize accept new connections at the hub.

Ill try to reduce to a test-case, but heres a quick look at the code 
fragment which (when run)
causes the problem (only on windows)




package Log;

.....

our $new_anote = 1;  # 0,1, both work on unix, neither on win

##############

# list of tags accepted by new, build rex from it
$Log::tags = join '|', qw(log play verbose load outdir check logmsgs 
anote);

sub new {
    my ($class, $opt) = @_;

    my %args = %$opt;
    # delete option tags which dont match approved list
    delete @args{ grep !/$Log::tags/, keys %args };

    # remaining are legal, add each to object
    my $self = bless {%args}, $class;

    if ($self->{anote} and $new_anote) {
      my $io = new IO::Handle;
      $io->fdopen(*STDIN, "r");
      $io->blocking(0);
      $self->{anote} = $io;
    }
......
}


sub snap {
    my ($self, $tag, $msg) = @_;

    print "snapping $tag\n";

    if ($self->{anote}) {
    # handle annotations on stdin b4 logging latest msg
    (my $atag=$tag) =~ s/[HC]$//;

    if (!$new_anote) {
        if (my $found = select(my $bits=$cbits,undef,undef,0)) {
        # got annotation, read it
        my $buf;
        sysread(STDIN, $buf, 10000);
        chomp $buf;
        print "you said: $buf, $atag\n";
        $logfh->print("${atag}A: <$buf> Ascii\n");
        }
    } else {
        foreach ($self->{anote}->getlines) {
        print "you said: $_, $atag\n";
        $logfh->print("${atag}A: <$_> Ascii\n");
        }
    }
    }
..........

 }





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