title: Call the "C++" Struct in C File
body: <p>I have a problem, that I explain below code, How Can I call the C++ struct in C file without any error ?</p>
  
  <p>I have a <code>C++</code> library in my code, in the this library include this defines:</p>
  
  <p>In the <code>C++</code> library code example.h:</p>
  
  <pre><code>struct P_BRIDGE;
  
    typedef void  (*CALLBACK_ENABLE_TRAPPING)          (const struct P_BRIDGE* bridge, bool enable, unsigned int timestamp);
      struct S_CALLBACKS
      {
          CALLBACK_ENABLE_TRAPPING        enableTrapping;
  
      };
  </code></pre>
  
  <p>And I want to call this struct in <code>main.c</code> file like this   </p>
  
  <pre><code>    #include example.h
  ....
          extern P_CALLBACKS const p_callbacks;
            P_BRIDGE* bridge = NULL;
  </code></pre>
  
  <p>`
   I have this error :</p>
  
  <pre><code>Src/main.c:175:24: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'const'
  Src/main.c:176:3: error: unknown type name P_BRIDGE'
  </code></pre>