BUG: Link Fails w/ Unresolved External When Call SWAP.H (123780)

The information in this article applies to:

Microsoft Visual C++, Macintosh Cross-Development Addon 4.0b

This article was previously published under Q123780

SYMPTOMS

When calling the functions defined in SWAP.H from a C++ program, the link fails with an unresolved external, such as this one:

   TEST.OBJ : error LNK2001: unresolved external symbol
    "?CbFreeSwapMem@@YCJJ@Z (long  __pascal CbFreeSwapMem(long))"
   TEST.OBJ : error LNK2001: unresolved external symbol
    "?SetMaxSwapSize@@YAXK@Z (void  __cdecl SetMaxSwapSize(unsigned long))"
   MacDebug/TEST.exe : error LNK1120: 2 unresolved externals

CAUSE

The header file (SWAP.H) in the MSVC20\M68K\INCLUDE directory is missing the necessary extern "C" block around the swap function declarations.

RESOLUTION

Surround the include of SWAP.H with an extern "C" block, as in this example:

   extern "C"
   {
   #include <swap.h>
   }

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Sample Code

   test.cpp
   #include <swap.h>
   void testFunc(void)
   {
      CbFreeSwapMem(2048);
      SetMaxSwapSize(4096);
   }

Modification Type:	Major	Last Reviewed:	2/11/2002
Keywords:	kbbug kbLangCPP KB123780