Re: DllMain implementation

From:

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Mon, 11 Feb 2008 10:02:38 -0600

Message-ID:

<u5t1tcMbIHA.5364@TK2MSFTNGP04.phx.gbl>

George wrote:

Thanks Will,

So you think the sequence of input object file matters? i.e. user
defined DllMain is always provided before default one?

Any if user provides one, there is no duplicated define symbol errors?

I know some compilers have the concept of a "weak" symbol, where the
duplicate definition warning is skipped.

regards,
George

"William DePalo [MVP VC++]" wrote:

"George" <George@discussions.microsoft.com> wrote in message
news:5CA28152-9BE7-45A4-8F67-20DA96A6A307@microsoft.com...

CRT is implemented a way that if developer provides DllMain, it
will use the
provided one, or else the default DllMain is used.

I am wondering how to implement similar selective linking approach?
i.e. if
there are more than one implementations of a method of the same
signature, I
can control which one has the higher priority to link, and if the
highest priority one does not exist, the second priority one will
be used (and compiler will have no duplicated method warning/error).

Here is what I'm sure of: The CRT has a source file named Dllmain.c.
The comments say it is used when no other version is provided.

Here is what I'm not sure of: I think that it is a simple matter
specifying Dllmain.obj on the linker command line but _after_ all of
the other object modules and libraries. If the reference is resolved
early, the CRT's Dllmain won't be linked. If not, it will

Regards,
Will