Re: IO Socket buffer flushing

in reply to IO Socket buffer flushing

1. use strict; use warnings; They are your friends, and will save you many many many hours of troubleshooting and head scratching. They aren't perfect, you'll still have to do some work, but certainly a lot less...

2. Keep your code layout tidy paying particular attention to indentation. It may feel awkward, even unnessesary at first, but it'll get easier and easier until you find yourself writing well layed out code without even thinking about it... In short, well layed out code will make your life easier.

3. Well done for posting a short example of your code that demonstrates the problem. In this particuar case it would also be worth posting an example of the output you are seeing. Often its easy to just stick __END__ on the end of your code post and paste your output below it.

4. I tried your code (modified slightly to conform to strict rules) and it seems to work fine. No weird buffering issues are apparent... If the revised code below don't solve the problem your having, please clarify with further details and what output your seeing. Cheers!

Your code slightly modified:

#server
use strict;
use warnings;

use IO::Socket; 

$| = 1;
my $nonblocking = 1;

         
my $sock = new IO::Socket::INET( 
    LocalHost   => "localhost", 
    LocalPort   => 7890, 
    Proto       => "tcp", 
    Listen      => SOMAXCONN, 
    Reuse       => 1,
    Timeout     => 20,
); 

if ($sock) {
   print "A socket created on LocalHost listening on LocalPort\n";
} else {
   die "Error - no listening socket created : $!"; 
}
my $flush = 1;

while (my ($new_sock,$c_addr) = $sock->accept()) {
    my ($client_port, $c_ip) = sockaddr_in($c_addr); 
    my $client_ipnum = inet_ntoa($c_ip); 
    my $client_host =gethostbyaddr($c_ip, AF_INET); 
    print "Got a connection from: $client_host"," [$client_ipnum] \n";
+ 
    print "Created new socket for reading or writing data to Client\n"
+;

    ioctl($new_sock, 0x8004667e, \$nonblocking);
    my $buf;
    
    sysread($new_sock, $buf, 10);
    print "$buf\n";
    syswrite($new_sock, $buf, 10);
    $new_sock->flush;
    sysread($new_sock, $buf, 1);
    print "$buf\n";
    $new_sock->flush;
    syswrite($new_sock, "12", 2);
}
[download]

#client
use strict;
use warnings;

use IO::Socket; 

#To flush the buffer print statements
$| = 1;  

my $sock = new IO::Socket::INET( PeerAddr => 'localhost', PeerPort => 
+7890, Proto => 'tcp'); 

if ($sock) {
   print "A tcp socket on localhost connected to 7890\n";
} 
else {
   die "Error: $!"; 
}

my $nonblocking = 1;
ioctl($sock, 0x8004667e, \$nonblocking);
my $buf = "1234567890";

syswrite($sock, $buf, 10);
sysread($sock, $buf, 10);
$sock->flush;

print "Bytes 10 = $buf\n";
syswrite($sock, "1", 1);
print "\n";
$sock->flush;

sysread($sock, $buf, 2);
print "Bytes 2 = $buf\n";

__END__
C:\Temp>perl client.pl
A tcp socket on localhost connected to 7890
Bytes 10 = 1234567890

Bytes 2 = 1234567890

C:\Temp>perl client.pl
A tcp socket on localhost connected to 7890
Bytes 10 = 1234567890

Bytes 2 = 1234567890

C:\Temp>perl client.pl
A tcp socket on localhost connected to 7890
Bytes 10 = 1234567890

Bytes 2 = 1234567890

C:\Temp>
[download]

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