Visual Studio not able to show the value of 'this' in release mode (with debug information)

Question

Original question:

Why is the this pointer 0 in a VS c++ release build?

When breaking in a Visual Studio 2008 SP1 release build with the /Zi

Answer 1

Local variables (including this) when viewed in the Locals window cannot be relied upon in the Release build in the way that they can in Debug builds. Whether the variable value shown is correct at any given instruction depends on how the underlying register is being used at that point. If the code runs OK in Debug it's most unlikely that the value is actually 0.

Optimization in Release builds makes values in the Locals window a crap shoot, to the naked eye. Without concurrent display and correlation of the Disassembly window, you cannot be sure that the Locals window is telling you the actual value of the variable. If you step through the code (maybe in Disassembly not Source) to a line that actually uses this, it's more likely that you will see a valid value there.