Upgrade a Plain TCP Connection to TLS

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Demonstrates Socket.ConvertToSsl, which upgrades an already-connected plain TCP socket to TLS by performing a client-side TLS handshake over the existing connection.

Background. This supports STARTTLS-style upgrades, where a protocol begins in plaintext and switches to TLS at a defined point. Perform the protocol-specific negotiation first, then call ConvertToSsl.

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#include <C_CkSocket.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSocket socket;
    BOOL bTls;
    int maxWaitMs;

    success = FALSE;

    socket = CkSocket_Create();

    //  Connect as plain TCP (no TLS yet).
    bTls = FALSE;
    maxWaitMs = 5000;
    success = CkSocket_Connect(socket,"example.com",5000,bTls,maxWaitMs);
    if (success == FALSE) {
        printf("%s\n",CkSocket_lastErrorText(socket));
        CkSocket_Dispose(socket);
        return;
    }

    //  At the point where the application protocol permits a STARTTLS-style upgrade, perform any required
    //  negotiation, then upgrade the existing connection to TLS with a client-side handshake.
    success = CkSocket_ConvertToSsl(socket);
    if (success == FALSE) {
        printf("%s\n",CkSocket_lastErrorText(socket));
        CkSocket_Dispose(socket);
        return;
    }

    printf("Connection upgraded to TLS.\n");


    CkSocket_Dispose(socket);

    }