Getting warning from C math library's pow function <p>I have the following function in my code:</p> <pre><code>int numberOverflow(int bit_count, int num, int twos) { int min, max; if (twos) { min = (int) -pow(2, bit_count - 1); \\ line 145 max = (int) pow(2, bit_count - 1) - 1; } else { min = 0; max = (int) pow(2, bit_count) - 1; \\ line 149 } if (num &gt; max &amp;&amp; num &lt; min) { printf("The number %d is too large for it's destination (%d-bit)\n", num, bit_count); return 1; } else { return 0; } } </code></pre> <p>At compile time I get the following warning:</p> <pre><code>assemble.c: In function ‘numberOverflow’: assemble.c:145: warning: incompatible implicit declaration of built-in function ‘pow’ assemble.c:149: warning: incompatible implicit declaration of built-in function ‘pow’ </code></pre> <p>I'm at a loss for what is causing this... any ideas?</p>