title: error: argument of type "void (opca_hello::)()" does not match "void* (*)(void*)"
body: <p>I have written a very simple code for threading. Since I am very new to this, I have no idea about the error mentioned.</p>
  
  <pre><code>class opca_hello
  {
   public:
  void hello();
  }
  
  void opca_hello::hello()
  
  {
  printf ("hello \n");
  }
  
  
  int main(int argc, char **argv)
  {
  opca_hello opca;
  pthread_t thread1, thread2;
  pthread_create( &amp;thread1, NULL, opca.hello, NULL);
  pthread_join( thread1, NULL);
  return 0;
  }
  </code></pre>
  
  <p>error: argument of type "void (opca_hello::)()" does not match "void* (*)(void*)"</p>