Re: Singleton MFC Extension DLL

From:

Stephen Myers <""StephenMyers\"@discussions@microsoft.com">

Newsgroups:

microsoft.public.vc.mfc

Date:

Fri, 08 Jan 2010 08:50:38 -0600

Message-ID:

<#iYoyHHkKHA.4772@TK2MSFTNGP04.phx.gbl>

MFDonadeli wrote:

With project dependencies, I can access all the classes and functions
on this DLL, and in the build line command the lib apper at the end of
the command.

And I think that if project dependencies is wrong the solution that I
describe, wouldn't compile:

In this case I can access the Singleton if I remove the variable
static CMySingleton* singleton and put on the Instance function like
this:
static CMySingleton* Instance()
  {
      static CMySingleton* singleton;
        if(!singleton)
                singleton = new CMySingleton();
    return singleton;
  }
but the problem in this case, is that this function create another
instance of CMySingleton, even if static singleton var is already
initialized.

Exactly when do you get the unresolved external link error? Is it with
the DLL or when you try to reference the DLL?

It looks like the problem is you have an inline class, apparently
defined completely within the .h file. Where is

CMySingleton* CMySingleton::singleton = NULL;

This would usually be in MySingleton.cpp, and would be part of the
regular dll you are creating. Is it?

Steve