What is the ## operator?
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/2025858/what-does-mean-for-the-cc-preprocessor">What does ## mean for the C(C++) preprocessor?</a>  </p>
</blockquote>



<pre><code>#define SIMPLE16_DESC_FUNC1(num1, log1) \
    bool                            \
    Simple16::try##num1##_##log1##bit(uint32_t *n, uint32_t len)    \
    {                                       \
            uint32_t        i;              \
            uint32_t        min;            \
\
            min = (len &lt; num1)? len : num1; \
\
            for (i = 0; i &lt; min; i++) {     \
                    if (int_utils::get_msb(n[i]) &gt; log1 - 1)        \
                            return false;   \
            }               \
\
                return true;    \
        }
</code></pre>

<p>I found this code in someone's code, it seems "##" operator plays an important role in the function name. Anyone tells me what its usage?</p>
