C++ : what is :: for?
<p>If you go to the accepted answer of this <a href="http://stackoverflow.com/questions/1012571/stdstring-to-float-or-double/1012604#1012604">post</a></p>

<p>Could someone please elaborate on why he uses:</p>

<pre><code>double temp = ::atof(num.c_str());
</code></pre>

<p>and not simply</p>

<pre><code>double temp = atof(num.c_str());
</code></pre>

<p>Also, is it considered a good practice to use that syntax when you use "pure" global functions?</p>
