title: Why am I getting a namespace identifier error?
body: <p>I am using Keil uVision and I keep getting this error:</p>
  
  <pre class="lang-none prettyprint-override"><code>C:\Keil_v5\ARM\ARMCC\bin\..\include\rw/_defs.h(781): error:  #20:
      identifier "namespace" is undefined
  </code></pre>
  
  <p>What could lead to this error? Isn´t namespace automatically defined?</p>