How can I debug Just My Code?

re: How can I debug Just My Code?

Daniel Moth — Fri, 31 Dec 2004 21:38:00 GMT

I haven't played with this feature yet but the obvious question is: What are the full differences between the DebuggerStepThroughAttribute and the DebuggerNonUserCode? It appears that one works at the source level while the other goes deeper, the latter should be faster than the former and that the new attribute can be turned on with a simple setting in the IDE whereas the old one has to be manually commented out. Are these statements correct and/or what other differences from a usage perspective are there?

re: How can I debug Just My Code?

Mike Stall — Sun, 02 Jan 2005 09:34:00 GMT

Daniel -
To be clear: The CLR ignores both attributes. They're defined in mscorlib.dll so that they're available for use by debugger applications (like VS).

The semantics are very similar in both(annotating "non-user" code). Hopefully we will document the semantics very clear in MSDN when we ship v2.0.

Thus the real difference between these attributes is entirely what a debugger does with them. In Visual Studios's case:
- DebuggerStepThroughAttribute is from v1.1. VS uses traditional step operations (pre-JMC_ to skip non-user code there.
- DebuggerNonUserCode is in v2.0 and VS uses this explicitly for the new JMC functionality above.

So maybe your question boils down to comparing (1) faking JMC with traditional step operations to (2) real JMC?

- Real JMC is much faster and can handle arbitrarily complex scenarios.
- Re: turning on + off: This is entirely a feature within VS. A debugger could just as easily have added a checkbox to ignore the DebuggerStepThroughAttribute . Or it could have just as easily removed the "Enable JMC" checkbox and thus forced you to comment out the DebuggerNonUserCode attribute.

re: How can I debug Just My Code?

Daniel Moth — Sun, 02 Jan 2005 18:14:00 GMT

Thank you, that helps. I don't see why DebuggerStepThrough does not go through the obsolescence path then, but that is an academic discussion I guess...

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