Unicode C

Check Whether SSH Channel EOF Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has been received for a channel. The only argument is the channel number. EOF means the server will send no more ordinary channel data, but it does not close the channel.

Background: EOF and CLOSE are separate events, and the distinction matters when deciding whether a command has truly finished. A server commonly sends EOF first and CLOSE afterward; in that interval this method is true while ChannelReceivedClose is still false, and the channel remains open and counted. EOF is the signal that all output has been produced — useful when you want to stop reading without waiting for the full close handshake. It returns false for an invalid, released, or locally closed channel.

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Unicode C

#include <C_CkSshW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSshW ssh;
    int sshPort;
    const wchar_t *password;
    int channelNum;

    success = FALSE;

    //  Demonstrates the Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has
    //  been received for a channel.  The only argument is the channel number.  EOF means the server
    //  will send no more ordinary channel data, but it does not close the channel.

    ssh = CkSshW_Create();

    sshPort = 22;
    success = CkSshW_Connect(ssh,L"ssh.example.com",sshPort);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    password = L"mySshPassword";

    success = CkSshW_AuthenticatePw(ssh,L"mySshLogin",password);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    channelNum = CkSshW_OpenSessionChannel(ssh);
    if (channelNum < 0) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    success = CkSshW_SendReqExec(ssh,channelNum,L"ls -l /tmp");
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    //  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    //  it, this call waits forever if the server never sends channel close.
    CkSshW_putReadTimeoutMs(ssh,15000);

    success = CkSshW_ChannelReceiveToClose(ssh,channelNum);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    if (CkSshW_ChannelReceivedEof(ssh,channelNum)) {
        wprintf(L"EOF was received -- no more ordinary channel data will arrive.\n");
    }
    else {
        wprintf(L"No EOF has been received.\n");
    }

    CkSshW_Disconnect(ssh);


    CkSshW_Dispose(ssh);

    }