FIX: Linker Errors on Array of Constant Pointers to Constants

    MODULE2.OBJ(module2.cpp) : error L2025: char const __near*
         __near* __near str : symbol defined more than once
    LINK returned error code 2.
					

    module2.obj: warning LNK4006: xxxxx already defined in
         module1.obj; second definition ignored.
					

   static const char *const str[2] = { "string1", "string2" };
				

MORE INFORMATION

In C++, const objects do not have external linkage, unless they are explicitly declared extern. Const objects have internal linkage, meaning that the name of the object is local to the source file in which it is declared.

The following sample code has two source files and one header file. The array of const pointers to const chars is included twice in the program. However, because this is C++, const objects should have internal linkage, the arrays should only be visible in the source file they are declared in. This means that the linker should not fail with an L2025 error, or report the LNK4006 warning.

Sample Code

// Compile options needed: None

// Test.h

const char *const str[] = { "string1" , "string2" };  // error

// Module1.cpp

#include "test.h"           // included test.h once in project.
#include <iostream.h>

void function1()
{
   cout << "In Function1" << endl;
}

// Module2.cpp

#include "test.h"          // included test.h twice in project
#include <iostream.h>

extern void function1();

void function2()
{
  cout << "In Function2" << endl;
}

void main()
{
  function1();
  function2();

  return;
}