 function returns an integer number in accordance with the <a href="API-notes.html#errors">return
        code convention</a>: positive if any system call has returned an error,
      negative (from the <a href="API-datastruct.html#LibRaw_errors">LibRaw
        error list</a>) if there has been an error situation within LibRaw.</p>
    <p>Before file opening, <a href="#recycle">recycle()</a> is always called;
      hence, if several images are processed in the batch mode, there is no need
      to call recy