If you have the raw bytestring, the easiest way to see if it's valid UTF-8 is to decode it to a unicode string. If that fails, it wasn't utf8 enough :) 

utf8::decode($string)
    or die "Input is not valid UTF-8";

[download]
or 
utf8::decode(my $text = $binary)
    or die "Input is not valid UTF-8";

[download]
If you leave out the "or die" clause, any invalid UTF-8 will just be seen as ISO-8859-1.

Update: changed the examples as per ikegami's sound response.

Juerd # { site => 'juerd.nl', do_not_use => 'spamtrap', perl6_server => 'feather' }

In reply to Re^3: i18n/utf8 problem, 'utf8 "\xF8" does not map to Unicode' by Juerd
in thread i18n/utf8 problem, 'utf8 "\xF8" does not map to Unicode' by bcrowell2

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