Re: exported symbols of shared libraries on MSVC

Hi Kirill,

> If you look at commands executed by libtool when it creates a DLL,
> you may see that it runs $NM on all object files which go into DLL.
> Then it uses some awk script to generate list of all `extern` symbols
> defined in those object files. Libtool then appends each symbol with
> `-link -export:` so link.exe will export all of them.
> ...
> I don't like how libtool handles this. This may result in unwanted
> symbols to be exported.
> 
> I wish we had some option to pass to LT_INIT() to disable this behavior,
> but keep old behavior as default.

I'm not the libtool maintainer, but I think the major reason for the
behaviour of "libtool --mode=link" on MSVC is to be compatible with
the behaviour on other platforms, in particular ELF-based ones.
On these platforms, when you create a shared library ("gcc -shared ..."),
it exports all global symbols.

Which set of symbols would you want to be exported by default?

Authors of shared libraries typically use one of various techniques [1]
to decide which symbols to export. There is no single technique for all
possible situations.

Bruno

[1] https://www.gnu.org/software/gnulib/manual/html_node/Exported-Symbols-of-Shared-Libraries.html