\param fname "short" filename (without path)
\param path the path (dir1:dir2,..) - ala Unix
\param base can be added to relative paths (NULL for no append)
\param fullpath the full path to filename (if successful)
\param fname "short" filename (without path)
\param path the path (dir1:dir2,..) - ala Unix
\param base can be added to relative paths (NULL for no append)
\param fullpath the full path to filename (if successful)