*a++

   int increment(a)

   {
      return a+1;
   }

   void somefunc()

   {
       int b = 5;

       b = increment(b);

       printf("b now %d\n", b);
   }

  T get_t(int how, char **error);
  int get_val(T *v);

  struct get_t_res {T; char *};
  struct get_t_res get_t(int);

  struct get_val_res {int; T};
  struct get_val_res get_val();

For the use cases that are too expensive to use functions, macros can be used instead.

However that is only if C++ cannot be used at all, otherwise don't bother.

that's latest GCC, at -O3

But yes, sadly I think it's still generally advisable to avoid returning large structs by value.

Note that this has nothing to do with RVO; as I understand it, RVO is about eliding copy constructors, not actual memory copies, and c has no copy constructors and so gets 'RVO' in all cases.

Noob mistake