I'm trying to push some files around using a couple of perl scripts and sockets, but have come up against an intermittent problem reading and writing data. Simply, my server is doing a syswrite, but my client's sysread doesn't receive all the data.

The sockets are created in the normal way 

    my $sock = IO::Socket::INET->new(PeerAddr => '127.0.0.1',
                                         PeerPort => '9090',
                                         Proto    => 'tcp')
      or die("Couldn't connect: $!");

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and 

    my $server = IO::Socket::INET->new( Proto     => 'tcp',
                                        LocalPort => $PORT,
                                        Listen    => 10,
                                        Reuse     => 0)
        or die("$!");

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and my read / write functions look like this 
# server
sub write {
    my ($self, $string) = @_;
    my $server_socket = $self->{SERVER_SOCKET};

    my $write_length = sprintf "%020d", length($string);
    syswrite $server_socket, $write_length, 20;

    print "Writing $write_length bits of data\n";
    syswrite $server_socket, $string, $write_length;

}

# client
sub read {
    my ($self, $param) = @_;
    my $sock = $self->get_socket();

    my $read_length;
    my $buffer;
    sysread $sock, $read_length, 20;
    sysread $sock, $buffer, $read_length;

    my $buffer_length = length($buffer);
    $buffer_length == $read_length 
      or die("Tried to read $read_length bits but only got $buffer_len
+gth bits\n");

    return $buffer;
}

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Which occasionally gives output like this. 
server
  ...
  Writing 00000000000000014848 bits of data

client
  
  Tried to read 00000000000000014848 bits but only got 13140 bits

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The really weird thing is that most times this will just work. My client and server are running on the same machine, which has active perl 5.10, and IO::Socket::INET is at version 1.31.

Ignoring the code and it's limitations (which I'll work on if I get this sorted), does anyone see why this might be failing every now and then?

Thanks,

Rob

---
my name's not Keith, and I'm not reasonable.

In reply to Missing data in IO::Socket::INET sysread/syswrite by reasonablekeith

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