Parameters

Return value

If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The SetEndOfFile function can be used to truncate or extend a file. If the file is extended, the contents of the file between the old end of the file and the new end of the file are undefined.

If the file is opened with FILE_APPEND_DATA access, the end of the file is always positioned at the end of the file for writes. Calling SetEndOfFile when a file is opened with FILE_APPEND_DATA access can lead to unexpected behavior.

This function moves the current file pointer to the new end of the file.

Requirements

See also

• CreateFile
• GetFileSizeEx
• SetFilePointerEx
• WriteFile

Example

// This code example shows how to use SetEndOfFile.
// It assumes hFile is a valid handle to a file opened with GENERIC_WRITE access.

HANDLE hFile = ...; // Obtain a handle to the file
LARGE_INTEGER newSize;
newSize.QuadPart = 1024; // Set the new end-of-file position to 1024 bytes

if (SetEndOfFile(hFile)) {
    // File successfully truncated or extended.
    // The file pointer is now at the new end-of-file.
    #ifdef _DEBUG
        OutputDebugString(L"SetEndOfFile succeeded.\n");
    #endif
} else {
    // Handle error
    DWORD error = GetLastError();
    #ifdef _DEBUG
        WCHAR buffer[256];
        wsprintf(buffer, L"SetEndOfFile failed with error code: %lu\n", error);
        OutputDebugString(buffer);
    #endif
}

// Remember to close the file handle when done
// CloseHandle(hFile);