Re: [C++ PATCH] warning about empty extern "C" structures

[Roman Kononov <kononov195-far at yahoo dot com>]

On 05/17/2006 22:08, Andrew Pinski wrote:
> On May 17, 2006, at 8:03 PM, Roman Kononov wrote:
>
> > extern "C" {
> >   static inline int foo(int socket) {
> >      struct empty_t {};
> >      struct network_message_t {
> >         empty_t foo;
> >         int stuff;
> >      } msg;
> >      msg.stuff=0;
> >      return send(socket,&msg,sizeof(msg));
> >   }
> > }
> >
> > We would like foo() to send same message from C++ and C code.
>
>
> That is just bogus.  Why have an empty struct in there in the first place.
> The only place empty structs come handy is where they don't store data
> and are needed to pass around as pointers like a lock (though I don't
> think that is a good use anyways).

It is not bogus. Instead of just

  struct empty_t {};

think about this:

  struct empty_t {
      #ifdef MSG_DEBUG
         int debug;
      #endif
      #ifdef MAGIC
         long magic;
      #endif
      /*and so on for few pages*/
  };

Roman