compiler may disallow the NUL character (U+0000) in the source text.
</p>
<p>
Implementation restriction: For compatibility with other tools, a
compiler may ignore a UTF-8-encoded byte order mark
(U+FEFF) if it is the first Unicode code point in the source text.
A byte order mark may be disallowed anywhere else in the source.
</p>

<h3 id="Characters">Characters</h3>

<p>