Language extensions and new keywords
<p>What does a standard say about extending a C++ language and adding 'non standard' keywords? Do the keyword have to start with __ (double underscore) or can the be 'regular', meaning starting with a letter?  If I would about to create extension to C++ and have a new keyword do I have to make it look like this:  </p>

<pre><code>__new_keyword  
</code></pre>

<p>or can it be just simple:  </p>

<pre><code>new_keyword.  
</code></pre>

<p>Thanks.</p>
