Unicode C

Write Text at a 64-bit Offset in a Remote SFTP File

Demonstrates the Chilkat SFtp.WriteFileText64 method, which encodes text and writes it at a specific 64-bit byte offset in an open handle. The arguments are the handle, the offset, the charset, and the text. The 64-bit offset supports very large files.

Background: A 32-bit offset tops out at about 4 GB, so files larger than that require the 64-bit form to address positions beyond that boundary. The behavior is otherwise identical to the 32-bit version — the only difference is the width of the offset argument, chosen to match the size of the file you are working with.

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Unicode C

#include <C_CkSFtpW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSFtpW sftp;
    int port;
    const wchar_t *password;
    const wchar_t *handle;
    __int64 offset;

    success = FALSE;

    //  Demonstrates the SFtp.WriteFileText64 method, which encodes text and writes it at a specific
    //  64-bit byte offset in an open handle.  The 1st argument is the handle, the 2nd is the offset,
    //  the 3rd is the charset, and the 4th is the text.  The 64-bit offset supports very large files.

    sftp = CkSFtpW_Create();

    //  Connect, authenticate, and initialize the SFTP subsystem.
    port = 22;
    success = CkSFtpW_Connect(sftp,L"sftp.example.com",port);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        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 = CkSFtpW_AuthenticatePw(sftp,L"mySshLogin",password);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        return;
    }

    success = CkSFtpW_InitializeSftp(sftp);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        return;
    }

    handle = CkSFtpW_openFile(sftp,L"subdir/hugefile.dat",L"readWrite",L"openOrCreate");
    if (CkSFtpW_getLastMethodSuccess(sftp) == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        return;
    }

    //  Write at a byte offset beyond the 32-bit (4 GB) range.
    offset = 5000000000;
    success = CkSFtpW_WriteFileText64(sftp,handle,offset,L"utf-8",L"MARKER");
    if (success == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        return;
    }

    success = CkSFtpW_CloseHandle(sftp,handle);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSFtpW_lastErrorText(sftp));
        CkSFtpW_Dispose(sftp);
        return;
    }

    wprintf(L"Wrote at the 64-bit offset.\n");

    CkSFtpW_Disconnect(sftp);


    CkSFtpW_Dispose(sftp);

    }