Debugging a release version of a DLL (with PDB file)

Question

If I have a DLL (that was built in release-mode) and the corresponding PDB file, is it possible to debug (step-into) classes/methods contained in that DLL?

If so, what are the required steps/configuration (e.g. where to put the PDB file)?

Edit:

If have the PDB file in the same place as the DLL (in the bin/debug directory of a simple console test application). I can see that the symbols for the DLL are loaded (in the Output window and also in the Modules window), but still I cannot step into the methods of that DLL.

Could this be the result of compiler optimizations (as described by Michael in his answer)?

Answer 1

The pdb is usually (for me at least) detected if it is next to the dll (like with the intellisense xml files).

Alternatively; you'll need a break point after the module has loaded...

At the break-point, bring up the "Modules" window (Ctrl+D,M - or Debug->Windows->Modules). Right click on your dll "Load symbols from", "Symbol path", etc.

Answer 2

Yes, you can debug release code with a PDB. There are some pitfalls however with debugging optimized code, more info here and here.

Your PDB just needs to be in a place that the debugger can find it - for local debugging same directory as the dll is usually easiest. Otherwise, put it in some place that the debugger can find it, and point the debugger to that place with the symbol path.