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

[Gabriel Dos Reis <gdr at integrable-solutions dot net>]

Roman Kononov <kononov195-far@yahoo.com> writes:

| > But not in GNU C:
| > GCC permits a C structure to have no members:
| >      struct empty {
| >      };
| >  The structure will have size zero.  In C++, empty structures are
| > part
| > of the language.  G++ treats empty structures as if they had a single
| > member of type `char'.
| Linux kernel, all written in C, has many empty structures. 

you mean in GNU C.  That is understood.

empty structures have been part of C++ since the dark ages, and the
behaviour of g++ matches the semantics of the language.  Notice that
g++ also implements the empty-base optimziations -- but those can be
(GNU) C anymore.

| They prevent from introducing safe C++ code.

I don't understand that comment.

-- Gaby