Exporting Classes from Static Libraries

Lance Lovette -- lovette@iftech.com
Tuesday, July 30, 1996

Environment: [VC 4.2, NT 3.51 SP4]

I am trying to move some MFC derived classes into both a static
library (.LIB) and a dynamic-linked library (.DLL). I haven't had
many problems exporting the classes from the DLL, but the LIB is
giving me a headache. No matter what I try, the linker cannot
resolve the symbols exported from the .LIB. I have tried an example
using a plain C++ object that only has a constructor, and I tried
linking to the extension libraries from David Schmitt's "Extending
the MFC Library". I can't get either one to work. So, my first
question is "Can this be done?". If so, my other questions are:

- Do I need to do anything special to export classes from
	a static library?
- Does it matter how my static library links to MFC? Which
	"MFC" option from the Settings Dialog should I use?
- Are there any subtle problems with exporting MFC classes from
	static libraries?
- Can you use precompiled headers when building the static
	library? If so, why do I get the message "fatal error
	LNK1211: precompiled type information not found;
	"Static Library\Debug/StdAfx.obj" not linked or overwritten"
	when compiling the application?

Thanks,

Lance
lovette@iftech.com

+-------------------------------------------------------------------+
Interface Technologies, Inc.

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Dave Kelly -- Dave_Kelly@ncs.com
Tuesday, August 06, 1996

Subject: Exporting Classes from Static Libraries
Author:  mfc-l@netcom.com at INTERNET
Date:    8/5/96 9:52 PM

Environment: [VC 4.2, NT 3.51 SP4]
     
I am trying to move some MFC derived classes into both a static 
library (.LIB) and a dynamic-linked library (.DLL). I haven't had 
many problems exporting the classes from the DLL, but the LIB is 
giving me a headache. No matter what I try, the linker cannot 
resolve the symbols exported from the .LIB. I have tried an example 
using a plain C++ object that only has a constructor, and I tried 
linking to the extension libraries from David Schmitt's "Extending 
the MFC Library". I can't get either one to work. So, my first 
question is "Can this be done?". If so, my other questions are:
     
     
     Here are the options I had to use in VC++ 1.52c to get this to work.  
     I don't use 4.2 (yet...don't ask), but these may help you out:
     
     The options I need to have set for Debug or Release to get a .LIB to 
     link are:
     
     /Gs        -       Code Generation | Disable Stack Checking
     /Gx-       -       Memory Model | Assume 'extern' and Uninitialized    
                                        Data 'far'
     /GA        -       Windows Prolog/Epilog | Protected Mode Application  
                                                Functions

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