Re: [Mingw-users] How to get Human readable DLL Function Names

[Mumit K. <khan@NanoTech.Wisc.EDU>]

On Fri, 29 Jun 2001, Rodrigo Hern=E1ndez wrote:

>=20
> Function__FRt5deque3Zt12basic_string3ZcZt18string_char_traits1ZcZt24__def=
ault_alloc_template2b0i0Zt9allocator1Zt12basic_string3ZcZt18string_char_tra=
its1ZcZt24__default_alloc_template2b0i0Ui0P13GeneralObjectRi=20
> @ 1 ; LoadMap(deque<basic_string<char, string_char_traits<char>,=20
> __default_alloc_template<false, 0> >, allocator<basic_string<char,=20
> string_char_traits<char>, __default_alloc_template<false, 0> > >, 0> &,=
=20
> GeneralObject *, int &)
>=20
> I make a change so it instad reads like this:
> Function =3D=20
> Function__FRt5deque3Zt12basic_string3ZcZt18string_char_traits1ZcZt24__def=
ault_alloc_template2b0i0Zt9allocator1Zt12basic_string3ZcZt18string_char_tra=
its1ZcZt24__default_alloc_template2b0i0Ui0P13GeneralObjectRi=20
> @ 1 ; LoadMap(deque<basic_string<char, string_char_traits<char>,=20
> __default_alloc_template<false, 0> >, allocator<basic_string<char,=20
> string_char_traits<char>, __default_alloc_template<false, 0> > >, 0> &,=
=20
> GeneralObject *, int &)
>=20
>=20
> then I use the DEF file to make an object file with exports like so:
>=20
> dlltool -d AeonScript.def -e exports.o -l libAeonScript.a AeonScript.o
>=20
> and compile
>=20
> gcc exports.o -oScript.dll
>=20
> this way I can call GetProcAddress with "Function" as paramether it works=
,=20
> however everytime I add a new function I have to go throw the process of=
=20
> creating a new def and changing every function entry again.

This is a tricky problem. C++, regardless of the compiler used, will=20
create mangled names, and loading a symbol at run using GetProcAddress=20
on Windows or dlsym/shl_findsym/etc on Unix all run into the same problem.

There are two ways to ease dynamically loading C++ functions:

1. Use "C" linkage for the functions. The names are then not mangled. For
each C++ function that needs to be dynamically loaded, I typically define
a second function using C linkage that just calls the intended one. The
indirection isn't necessary, and depends on your design/taste.

2. Use a "mangler" algorithm. I used this mechanism a long time ago, but
gave up because various C++ compiler vendors don't release the algorithm
used, and also the C++ ABI hasn't been stable on most platforms. If you
*only* use GNU C++, then this is a good method.

I recommend (1), with whatever local variations you need to make it work
for you.

This is not a GNU specific issue, but a C++ issue, and you'll have to deal
with for all compilers.

Regards,
Mumit