C++: "unqualified" linkage

[Martin v. Loewis]

> Hey, but wait!  What's wrong with using the plain old `extern "C"' to
> accomplish the same as your proposed extension?

Good question. The only answer I can think of right now is that it
would break the ABI. Also, consider

struct S{};

void foo(S*){}
namespace N{
  extern "C" {
    struct S{};
  }
}

void foo(N::S*){}


void main()
{
  S x;N::S y;
  foo(&x);
  foo(&y);
}

In Standard C++, this is a valid program. With that extension, that
would not be the case anymore (violation of the ODR). I don't know how
serious a problem that would be.

Regards,
Martin