Is Richter mistaken when describing the internals of a non-virtual method call?

Question

I would write this question directly to Jeffrey Richter, but last time he didn\'t answer me :) so I will try to get an answer with your help here, guys :)

In the book \"

Answer 1

From my understanding, and using your example: Under the hood:

A VIRTUAL method in a base class WILL have an entry in a derived class method table. This means that all the virtual methods in the 'object' type are available in all their derived classes method table.

A NON virtual method (as in the example code), with no supplied functionality in the derived classes will NOT actually have an entry in the derived classes method tables!

To check this, I ran the code in WinDbg to examine the method table for the Manager class.

MethodDesc Table Entry MethodDe JIT Name

506a4960 503a6728 PreJIT System.Object.ToString()

50698790 503a6730 PreJIT System.Object.Equals(System.Object)

50698360 503a6750 PreJIT System.Object.GetHashCode()

506916f0 503a6764 PreJIT System.Object.Finalize()

001b00c8 00143904 JIT Manager..ctor()

0014c065 001438f8 NONE Manager.GenProgressReport()

So,I can see the virtual object methods of object, but I can't see the actual method GetYearsEmployed since it's not virtual and has no derived implementation. Incidentally, by the same concept, you can't see the SomeOtherMethod function in the derived class either.

You can, however, call these functions, it's just they are not there in the method table. I could be incorrect, but I believe the call stack is walked to find them. Maybe this is what Mr Richter means in his book. I find his book difficult to read but that's because the concepts are complicated and he is cleverer than me :)

I'm not sure the IL reflects the problem. I believe it's possibly a layer below IL which is why I've used Windbg to take a look. I suppose you could use windbg to see of it walks the stack....