title: 'powf' is not a member of 'std'
body: <p>I have an error while compiling a library using XCode:</p>
  <blockquote>
  <pre><code>'powf' is not a member of 'std'
  </code></pre>
  </blockquote>
  <p>The <code>&lt;cmath&gt;</code> is included.</p>
  <p>Can someone explain to me what is going wrong?</p>