title: multiple definition and namespace
body: <p>Is that the right way to have functions in namespace that i will #include in multiple files?      </p>
  
  <p>test.h </p>
  
  <pre><code>#pragma once
      #ifndef TEST
      #define TEST
      namespace test{
      namespace {
  
          bool test(){
              return true;
          }
      }
  }
  #endif //TEST
  </code></pre>