List of unsupported unicode characters?

[email protected] (John Costello) Tue, 9 Jan 2007 23:10:05 -0800 (PST)
Newsgroups perl.unicode
Message-ID <Pine.LNX.4.44.0701092226060.25530-100000@olivia.indeterminate.net>
Is there a list of utf8 characters that perl cannot map, for example 
"\xA0"?  This is with Perl 5.8.3.