PRB: Extra Copies of Function Added to Library

• The Library Manager (LIB.EXE) included with: - Microsoft Visual C++ 32-bit Edition, 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

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

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

Keywords          : LibIss
Version           : 1.0 2.0 5.0
Issue type        : kbprb