Is gentemp or gensym "safe"?

[Rob Browning]

I'm nearly finished implementing srfi-11 using define-macro, and while
let*-values was fairly easy to implement elegantly, let-values is
somewhat uglier, and I need to create safe temporary values in the
expansion.  Is that possible with gensym or gentmp?

The documentation for gentemp seems off, indicating it takes 2
optional args, when in fact it takes only one.  Also, if you specify a
prefix to gensym, it starts generating very simple symbols.  These are
guaranteed not to conflict with the existing bindings, right?

Thanks

-- 
Rob Browning <address@hidden> PGP=E80E0D04F521A094 532B97F5D64E3930