BUG: Debugger Cannot Watch Function Returning struct or union

• The Integrated Debugger, used with:
  • Microsoft Visual C++, 32-bit Editions, versions 5.0, 5.0sp1, 5.0sp2, 6.0

SYMPTOMS

Adding a function call in the Developer Studio debugger Watch window may result in the following message if the function returns a struct or union with a field width greater than 4 bytes:

Error: cannot display value

RESOLUTION

There is no workaround for this problem.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

The following procedure reproduces this problem:

1. Create a new console application project and add the following file to the project:

   
         /* File: TEST.CPP */ 
   
          struct _XX
              {
              char   m1;
              char   m2;
              char   m3;
              char   m4;
              } XX;
   
          struct _XX fun()
          {
              return XX;
          }
   
          int main()
          {
              fun();
              return 0;
          } 




2. Build the project.



3. Click Build|Start Debug|Step Into on the Developer Studio menu.



4. Goto the Watch window by selecting View|Debug Windows|Watch.



5. Add the following watch expression in the "Name" column: fun()

Additional query words:

Keywords : kbDebug kbide kbVC500bug kbVC600bug
Version : winnt:5.0,5.0sp1,5.0sp2,6.0
Platform : winnt
Issue type : kbbug