t to use
     `access?' to predict the result of an open or execute, instead
     simply attempt that and catch any exception.

     The main use for `access?' is to let a set-UID/GID program
     determine what the invoking user would have been allowed to do,
     without the greater (or perhaps lesser) privileges afforded by the
     effective ID.  For more on this, see ``Testing File Access'' in The
     GNU C Library Reference Manual.