Q113065: PRB: Extra Copies of Function Added to Library

Article: Q113065
Product(s): Microsoft Programming Utilities
Version(s): 1.0 2.0 5.0
Operating System(s): 
Keyword(s): kbVC100 kbVC200 kbVC500 kbVC600
Last Modified: 06-MAY-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- The Library Manager (LIB.EXE), included with:
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 5.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

If a function is contained in a library being added to another library, and that
function already exists in the library being added to, LIB.EXE adds it anyway.
The following warning is generated:

  LNK4006: <function name> already defined in <library name>
  <object module name>; second definition ignored

The .OBJ file is added to the library, and can be added multiple times.

CAUSE
=====

This behavior is by design.

RESOLUTION
==========

If you add an object module that is already in the library, the new object
module replaces the old one. However, if you combine libraries, they are always
combined because there could be similarly named object modules in several
different libraries that don't have any of the same functions. The above warning
is generated to indicate conflicting function names.

MORE INFORMATION
================

Examining the contents of the library with the DUMPBIN utility

  DUMPBIN <library name> /symbols

shows multiple copies of the function exist in the library. The DUMPBIN utility
is in the \MSVCNT\BIN directory.

Sample Code
-----------

  /* FILE A.C
     Compile options needed: /c
  */ 

  #include <stdio.h>
  void amain(void)
  {
      printf("a");
  }

  /* FILE B.C
     Compile options needed: /c
  */ 

  #include <stdio.h>
  void bmain(void)
  {
      printf("b");
  }

  /* Lib commands needed: */ 
  /* Create the libraries TEST.LIB and TESTB.LIB   */ 

     lib /out:test.lib a.obj
     lib /out:testb.lib b.obj

  /* Add the contents of TESTB.LIB (B.OBJ) to TEST.LIB:     */ 

     lib test.lib testb.lib

  /* List the current contents of TEST.LIB;                   */ 
  /* it will show one copy of A.OBJ and one copy of B.OBJ.    */ 

     lib test.lib /list

  /* Add the contents of TESTB.LIB (B.OBJ) to TEST.LIB again. */ 
  /* This step generates the above warning.                   */ 

     lib test.lib testb.lib

  /* List the current contents of TEST.LIB;            */ 
  /* it will show two copies of B.OBJ in the library.  */ 

     lib test.lib /list

Additional query words:

======================================================================
Keywords          : kbVC100 kbVC200 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbLibSearch kbLibManExe
Version           : 1.0 2.0 5.0
Issue type        : kbprb

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