Re: gcc visibility used by moz

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

Tristan Wibberley <maihem@maihem.org> writes:

| Daniel Jacobowitz wrote:
| > On Wed, Jul 12, 2006 at 02:04:37AM +0100, Tristan Wibberley wrote:
| >> If the programmer had intended that the type should appear to not
| >> exist. it wouldn't be defined in a header #include-able by client
| >> code. The
| > GCC doesn't know if the header is includable by client code; I assume
| > that's the use Jason intended for marking classes hidden ("it belongs
| > to this shared object and no one else can see it").
| 
| 
| No, that's why we need programmer provided attributes. The programmer says:
| 
| "the client code needs to know about the existence of this type so it
| can get pointers and references to instances and pass them back in
| later and maybe be able to call virtual member functions and access
| non-static members" by putting it in a header which they document
| should be included by client code - thus client code includes it and
| knows about the type. But the programmer says:

It strikes as you are assuming C and C++ have a notion of module.
They don't.  They have the notion of "translation unit."  C++ adds the
notion of "One Definition Rule" to make sure Bad Things don't happen.
You have to operate within that framework if you're going to touch the
C++ type system in any way.

-- Gaby