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.

Chilkat C++ Downloads

Download Chilkat for C++

C++

#include <CkSFtp.h>

void ChilkatSample(void)
    {
    bool 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.

    CkSFtp sftp;

    //  Connect, authenticate, and initialize the SFTP subsystem.
    int port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        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.
    const char *password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    success = sftp.InitializeSftp();
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    const char *handle = sftp.openFile("subdir/hugefile.dat","readWrite","openOrCreate");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  Write at a byte offset beyond the 32-bit (4 GB) range.
    __int64 offset = 5000000000;
    success = sftp.WriteFileText64(handle,offset,"utf-8","MARKER");
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    success = sftp.CloseHandle(handle);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Wrote at the 64-bit offset." << "\r\n";

    sftp.Disconnect();
    }