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Perl

Send a 4-byte Length Prefix over a Socket

See more Socket/SSL/TLS Examples

Demonstrates Socket.SendCount, which sends a four-byte length prefix in network byte order. This is typically used to tell the peer how many bytes follow.

Background. A length-prefixed framing scheme sends the byte count of a message before the message body, so the receiver knows exactly how many bytes to read with a counted receive.

Chilkat Perl Downloads

Perl
use chilkat();

$success = 0;

$socket = chilkat::CkSocket->new();

#  Connect to the server using TLS.
$bTls = 1;
$maxWaitMs = 5000;
$success = $socket->Connect("example.com",5000,$bTls,$maxWaitMs);
if ($success == 0) {
    print $socket->lastErrorText() . "\r\n";
    exit;
}

#  Send a four-byte length prefix in network byte order.  A common framing pattern is to send the
#  number of bytes in a message before the message itself, so the peer knows exactly how many bytes
#  to read.
$messageLength = 512;
$success = $socket->SendCount($messageLength);
if ($success == 0) {
    print $socket->lastErrorText() . "\r\n";
    exit;
}

print "Length prefix sent." . "\r\n";