Re: Re: boost::intrusive_ptr and Managed C++?

From: Holger Grund (yg-boost-users_at_[hidden])
Date: 2003-08-21 07:50:09

"Ferdinand Prantl" <ferdinand.prantl_at_[hidden]> wrote

> The second option (as Holger says) is to make a simple facade to the
c++
> library (all you might use), which will not have templates (here
smart
> pointers) on the interface, and to use this facade instead.
>
Did I say that? Anyway, I absolutely agree.

I just want to point out that IMHO the best solution is to _not_
export instrusive_ptr_add_ref and _release.
If you do new and delete are called from different modules which
works only if the same CRT instance is used. And that works only if
both link against the exact same version of the CRT dll (that is both
linking against a static CRT still yields to instances => two heaps
=> error).

While we're at it, it's almost always a bad thing to export classes
or functions that rely on classes from a DLL. DLLs are a run time
concept. They don't have any clue which version of the
compiler a consumer is built with.

E.g. say you export a function
void foo( std::string& s )
{
    s = "Hello World!";
}

The DLL is built with the version A of the compiler and STL
and the consuming application is built with version B. There is
no guarantee for a binary compatibility between the two
version. And indeed the code above will break if version
6 & 7 of VC are used (The former used a COW scheme
while the second uses a short string optimization).

Also, do note that the DLL CRT now supports side by side sharing.

While I am in rant mode the catch(...) thing is also a very bad idea
in VC. This currently catches (this will be fixed in 8.0) structured
exception that are not C++ exception. That way serious error
conditions are silently ignored.

-hg