I think that it shuold be very interesting to see numerical return code and his define or enum value text in debug mode.
For example: ----------------------------------- #define S_OK 0
...
HRESULT foo(void) { ... return S_OK; }
...
void foo2(void) { HRESULT ret = foo(); } -----------------------------------
In debug mode, when tooltip appears it will could display "0 (S_OK)". I think that it would be more interesting for the codes defined in the MSDN than private codes.
VAX can not access debug information, if I understood correctly. But to see this kind of information, just add a watch variable like "ret,hr". Adding ",hr" tells VC that this is a HRESULT and should be interpreted, which it does nicely by showing you error number and the text, if it can find any.