How to ask Windows to open an external file based on file association?

HINSTANCE ShellExecute(
    HWND hwnd,            // handle to owner window.
    LPCTSTR lpOperation,  // verb to do, e.g., edit, open, print.
    LPCTSTR lpFile,       // file to perform verb on.
    LPCTSTR lpParameters, // parameters if lpFile is executable, else NULL.
    LPCTSTR lpDirectory,  // working directory or NULL for current directory.
    INT nShowCmd          // window mode e.g., SW_HIDE, SW_SHOWNORMAL.
);