C++

Abort a Running SSH Tunnel Operation

Demonstrates the AbortCurrent property, which requests that the currently running foreground operation be aborted. It is intended to be set to true from another thread — for example, to interrupt a synchronous Connect that is waiting for an unresponsive server.

Background: A synchronous call like Connect blocks the calling thread until it finishes or times out, which is a problem when a user clicks "Cancel" or the app needs to shut down. Setting AbortCurrent from a different thread breaks the blocked operation out early, returning a failure the caller can handle. Note its scope is deliberately limited to the current foreground operation: it does not stop the background listener or terminate established tunnel clients — use StopAccepting or CloseTunnel for those.

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C++

#include <CkSshTunnel.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the SshTunnel.AbortCurrent property, which requests that the currently running
    //  foreground operation be aborted.

    CkSshTunnel tunnel;

    //  AbortCurrent is intended to be set to true from ANOTHER thread to interrupt a synchronous
    //  operation in progress -- for example, a Connect that is waiting for an unresponsive server.
    //  It does not stop the background listener or terminate established background tunnel clients.
    //  
    //  The assignment below illustrates the property.  In a real application it would be set on a
    //  separate thread while Connect blocks; if it becomes true, the blocked Connect returns with a
    //  failure.
    tunnel.put_AbortCurrent(false);

    tunnel.put_DestHostname("db.internal.example.com");
    tunnel.put_DestPort(5432);

    int sshPort = 22;
    success = tunnel.Connect("ssh.example.com",sshPort);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Connected." << "\r\n";

    bool waitForThreadExit = true;
    success = tunnel.CloseTunnel(waitForThreadExit);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }
    }