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C++

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 C++ Downloads

C++
#include <CkSocket.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkSocket socket;

    //  Connect to the server using TLS.
    bool bTls = true;
    int maxWaitMs = 5000;
    success = socket.Connect("example.com",5000,bTls,maxWaitMs);
    if (success == false) {
        std::cout << socket.lastErrorText() << "\r\n";
        return;
    }

    //  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.
    int messageLength = 512;
    success = socket.SendCount(messageLength);
    if (success == false) {
        std::cout << socket.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Length prefix sent." << "\r\n";
    }