title: curl WRITEFUNCTION and classes
body: <pre><code>class Filter{
  private:
      string contents;
      bool Server(void);
  public:
      void handle(void *, size_t, size_t, void *);
     };
  </code></pre>
  
  <p>i have a class header like this. i want to call curl WRITEFUNCTION inside the function Server which would use handle to write to the string contents.
  although it keeps giveng me the error </p>
  
  <pre><code>error: invalid use of member (did you forget the ‘&amp;’ ?)
  </code></pre>
  
  <p>the line pointed by error is that of CURLOPT_WRITEFUNCTION.... My curl request looks something like this...</p>
  
  <pre><code>curl_easy_setopt(curl,CURLOPT_URL, address.c_str());
  curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,handle);
  curl_easy_perform(curl);
  </code></pre>
  
  <p>that means its unable to access the handle()..
  how can i rectify this?</p>