Re: Binary compatibility of boost dll files

From: Rene Rivera (yg-boost-users_at_[hidden])
Date: 2003-07-24 10:06:42

In article <bfn6e5$o3l$1_at_[hidden]>,
 "Rodolfo Lima" <yg-boost-users_at_[hidden]> wrote:

> I see that several boost libraries can be compiled as dll files. I'd like to
> know if there's any concern about binary compatilibity between different
> versions of those dll's as boost's version number (and possibly the library
> itself) changes. For instance, whenever MFC's dll binary interface changes,
> we have another library version written in it's name (MFC42.dll, MFC70.dll,
> MFC71.dll...), this way we can help avoiding "dll hell". 

Yes there is a concern with binary compatability from version to version. 
Because of the nature of C++ and Boost different versions of the code have no 
real hope of compatability :-(

We've discussed in some of the Boost devel lists about such problems. And we 
are trying to address them. To make things more interesting it's not just a 
matter of having version numbers, but also what the compiler was, and some 
indication of what compiler features got used to compile the code.

I have some changes to the build system which already does most of what's 
needed so if you are desperate for a fix try getting these files from CVS: 
http://tinyurl.com/hx8p and http://tinyurl.com/hx9i

>It would be also
> cool to link a version resource in each dll. This way, installers would
> check if a newer dll exists in the system, avoiding overwriting with an
> older one.

Now that's a harder proposition :-) Unlike Unix where it's easy to add the 
equivalent with a single command line argument to the compiler. It's hard to 
generate that version resource and compile/link with the various tools that do 
and don't come with compilers. Of course if someone knows of a way to put such 
resources directly into a C source file, I'd love to know ;-)

> And one last thing... the import library of date_time's dll isn't being
> generated, making it unusable. It's better to delete the dll target of its
> jamfile.

The files I point to above have that part commented out in fact :-)

> If any help of my part is needed, I'd be glad to help.

In that case, definately try out the alternate build files and tell me what 
you think. But I would suggest subscribing to the Boost.Build(jamboost) list, 
see http://www.boost.org/more/mailing_lists.htm if you want to get more 
involved in build issues.

-- 
-- grafik
-- Don't Assume Anything