Re: c++ class with member of function pointer type

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Mon, 25 Sep 2006 18:59:37 -0400

Message-ID:

<ueucHZP4GHA.4196@TK2MSFTNGP05.phx.gbl>

scott mcfadden <nospam.smcfadden@criticaltech.com> wrote:

I have a class that defines a function pointer type via a typedef.
This class has a member of that function pointer type that gets set
via a class constructor. I would like this class to be able to do
call backs to external functions via this mechanism but am having
linking problems. I am unsure of the correct way to export the class
/ typedef. Basically, I am trying to perform c# delegate type
functionality. What is the proper way to define the function pointer
and class so they are exported with correct linkage?
namespace Critical

{

typedef __declspec(dllexport) void (*LogEvent)(LOG_LEVELS level,
TCHAR* detail);

You cannot use __declspec(dllexport) with a typedef. It does not make
any sense - types don't get exported. A function pointer can point
equally well to an exported or non-exported function, without any
additional qualifiers. Just drop __declspec here.

class __declspec(dllexport) CallbackLogger : public LoggerBase

What little code you show looks good to me (modulo the correction
above). What specifically seems to be the problem?
--
With best wishes,
Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925