Re: Unicode and Multi-byte when linking

From:

"Tom Serface" <tom@nospam.camaswood.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Tue, 27 Jan 2009 09:17:56 -0800

Message-ID:

<89592724-26C5-43E3-8A15-87CC315C2098@microsoft.com>

I typically just have a different DLL for each "type" of build and name it
appropriately. For example:

MyDLL_ud.dll - Unicode debug
MyDLL_u.dll - Unicode
MyDLL.dll - ANSI
MyDLL_d.dll - ANSI debug

Then I link the appropriate one in based on the properties in my project.

Tom

"BoHuang" <BoHuang@discussions.microsoft.com> wrote in message
news:239F9FA7-0687-4BF1-BACE-B586CAF3FC51@microsoft.com...

Thanks. I certainly overlooked the #ifdefs, as the struct for both
versions
are simultaneously defined.

I guess one has to try both when given a a DLL without source, especially
with this sort of function parameter.

Would I encounter this error if instead this struct is in the body of the
function as a local variable rather than a parameter in the function
signature? I assume no.

"Giovanni Dicanio" wrote:

"BoHuang" <BoHuang@discussions.microsoft.com> ha scritto nel messaggio
news:374A994A-BE08-484E-9B14-1640E6FBA125@microsoft.com...

I recently had to use a DLL in which this function:

protected:
virtual BOOL PreCreateWindow( CREATESTRUCT& cs );

just cannot be found by the linker.

I came across an old thread that instructs to change my project setting
from
Unicode to Multi-byte. Thereafter the linker found the function.

Why is this the case? Could it be due to the LPCSTR in CREATESTRUCT?

If you go to the Win32 SDK file <winuser.h>, you can see that there are
two
"CREATESTRUCT's": CREATESTRUCTA (for ANSI/MBCS), and CREATESTRUCTW (for
Unicode).
So, on a ANSI/MBCS build, your PreCreateWindow is actually like this:

virtual BOOL PreCreateWindow( CREATESTRUCTA & cs );

Instead on a Unicode build, CREATESTRUCTW is used:

virtual BOOL PreCreateWindow( CREATESTRUCTW & cs );

This explain the linking mismatch.

How can I know if any DLL requires this sort of fix?

In general, I would expect something like this whenever you have some
form
of string pointer (e.g. LPCTSTR).

Giovanni