FIX: Can't Watch Values of Nondimensioned Array Parameters

The information in this article applies to:

• The Visual Workbench Integrated Debugger included with:

      - Microsoft Visual C++ for Windows, versions 1.0, 1.5, and 1.51
  

SYMPTOMS

When trying to view an array of pointers that is passed to a function as a nondimensioned array, the debugger cannot display the array's values or displays incorrect values. This happens with both CodeView and the Visual C++ integrated debugger. The source file must be a C++ source file with a .CPP or .CXX extension.

RESOLUTION

This problem is actually a special case of the one described in Knowledge Base article Q112984. The workaround is the same as in Q112984, with an additional step:

Declare the function argument as a pointer rather than an array, as stated in article Q112984. For example, change a declaration that uses the array syntax:

   void Function( char* Array[5] )

   void Function( char Array )

STATUS

Microsoft has confirmed this to be a bug in the products listed at the beginning of this article. This problem was corrected in Visual C++ 1.52.

This is not a problem in the 32-bit debugger.

MORE INFORMATION

The following sample demonstrates this problem. Step into the functions "ShowString()" and "ShowDoubles()", expanding "ary_pchar" and "dA", respectively, in the locals window. The values are not displayed correctly here or in the watch window if a watch is set on them.

Sample Code

// compiler options: /Zi /Od

   #include <stdio.h>

   // void ShowString( char ary_pchar )  // switch these two lines to
   void ShowString( char* ary_pchar[] )  //   fix the problem
   {
       printf( "%s", ary_pchar[1] );     // break here
   }

   // void ShowDoubles( double dA )      // switch these two lines to
   void ShowDoubles( double *dA[] )      //   fix the problem
   {
       int i;
       for (i = 0; i < 5; i++) {         // break here
           printf( "%lf\n", *dA[i] );
       }
   }

   void main(void)
   {
       char  str[] = "TEST\n";
       char* strArry[5];
       double d[5], *pD[5];
       int i;

       strArry[1] = str;
       for (i = 0; i < 5; i++) {
           d[i] = i;
           pD[i] = &d[i];
       }

       ShowString( strArry );
       ShowDoubles(pD);
       for (i = 0; i < 5; i++) {
           printf( "%lf\n", d[i] );
       }
   }