CP4349 - Debugging Autodesk® Product Plug-ins

1. CP4349 - Debugging Autodesk® Product Plug-ins Two bytes meet. The first byte asks, “Are you ill?” The second byte replies, “No, just feeling a bit off.” Kevin Vandecar Principal Developer Consulting Engineer – M&E Sparks Autodesk Developer Network

2. bio: Kevin Vandecar • @ Autodesk for over 18 years • all customization related • Experience with AutoCAD, AutoCAD Architecture, 3d Studio (DOS), Autodesk Revit • Last five years as Software Engineer on AutoCAD Architecture API and Revit API • now focusing on 3ds Max customization in ADN Sparks team • Based in Manchester, New Hampshire, US • email: kevin.vandecar@autodesk.com

3. Autodesk Developer Network • Access to almost all Autodesk software and SDK’s • Includes early access to beta software • Members-only website with thousands of technical articles • Unlimited technical support • Product direction through conferences • Marketing benefits • Exposure on autodesk.com • Promotional opportunities • One to three free API training classes • Based on user level www.autodesk.com/joinadn

4. What are we covering… • Most “plug-ins”, “add-ins”, “apps”, etc. for Autodesk applications are DLLs • Use mainly the C++ language to demonstrate debugging techniques in AutoCAD and 3ds Max • Touch on managed debugging, using Revit as an example. • Take a look at how CER mini-dump may be helpful for you • Look at the Visual Studio debugging tools • Nearly all of the techniques are the same between native (C++) and managed (C#, VB.NET, etc.)

5. Debugging… • …is fundamentally problem solving "Intellectuals solve problems, geniuses prevent them." - Albert Einstein

6. What is Debugging? aka: Autodesk plug-in developers!  Autodesk Application plug-in 2 plug-in 1 plug-in 3 Wikipedia: Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware, thus making it behave as expected. Debugging tends to be harderwhen various subsystems are tightly coupled, as changes in one may cause bugs to emerge in another.

7. What is Debugging? • For the “coder” much easier to understand at the implementation time • Code-time testing is important! aka Unit Testing • document your code! • For the “inspector/debugger” much harder • You may be debugging other people’s code • Or it may be code from your distant past • This makes it much more difficult

8. How to debug? Swigert: 'Okay, Houston, we've had a problem here.' Houston: 'This is Houston. Say again please.' Lovell: 'Houston, we've had a problem. We've had a main B bus under-volt.' • First verify problem and reproduce it… • No use setting break points, stepping through code, etc. without knowing how to repro it. • helps to document steps • smallest repro steps/sample is ideal • When communicating API problems beyond your code to Autodesk, it is ideal to have the smallest repro sample code possible.

9. How to debug? • Start Debugging! • Use the tools you have • The debugger itself is not the only tool! • Then once you found the problem… • Find the entry point into necessary code branch • If you have a complex plug-in, sometimes UI resource strings can help to find how to enter the code branch

10. How to Debug Autodesk Plug-ins? – different techniques • Coding Techniques • Additional Application specific options • Visually Inspect the Code • Use VS debugging tools • Reminder, VS2010 C++ Project Format used for 3ds Max and AutoCAD 2012 SDKs, but targeting VS2008 SP1 for binary compatibility (V90 toolset). • Revit is also using the VS 2010 managed compiler directly. • CER mini dump files

11. Coding techniques • Simplest form: Use Output statements • Debugger output(OutputDebugString) • Application output (“printf”, “cout”, and other routines) • Sometimes apps have their own output means • 3ds Max: MaxMsgBox, MAXScriptmprintf • AutoCAD: acutPrintf, acedAlert • Revit: TaskDialogs • Other Debug code statements • http://msdn.microsoft.com/en-us/library/ms679303(v=VS.85).aspx

12. Coding Techniques demo (acad) • Assert • code safety to ensure conditions are always met • Useful during dev cycle and all testing • #if <NAME> Pre-Processor statements • Technique can be used for “asserting” or other debug output in production code • Use project “variable” to set/unset, then very easy to enable/disable during build process

13. Additional Application specific options • Exploit application specific tools • For example: • Revit has RevitLookup API sample and debugging tool • AutoCAD • has ArxDbg and ArxDbgMgd (also vertical versions for ACA and AME) • Public symbol server (pdbs) • 3ds Max • Create routines that work in MAXScript context • has a full debug build with symbols and with some base source code • Public symbol server (pdbs)

14. Visually Inspect the Code • If you have a large team of developers, source control can help • Source Control differences between old and new versions of source code • Look at file history to find out who made changes

15. Use Debugging Tools – Visual Studio demo • Visual Studio IDE • VS 2010 and VS2008 IDEs are very similar for debugging • VS “global” Debugger Settings • Tools, Options, Debugging • Debug, Options and Settings • Consider Turning on Exception settings

16. VS Debug Project settings demo • Debugger “type” • Auto • Managed • Native Only • Mixed-mode (very useful with C++/CLI together with C++) • Edit and Continue (useful especially when learning)

17. VS Debug Project settings • Caveat for x64 vs. win32 (x86) projects • Edit and Continue STILL not supported in VS2010 for x64 targets • x64 Mixed-mode debugging also not available for .NET Framework 3.5 and prior. Only works in .NET Framework 4. The good news is that .NET Framework 4 is now supported by many Autodesk apps, but a C++ project has to be modified manually. • See: http://adn.autodesk.com/adn/servlet/devnote?siteID=4814862&id=16002138&linkID=4900509 • Can build x86 targets and run under WOW, but some Autodesk apps are not supported as x86 on x64 Operating Systems (NOTE: 3ds Max is!)

18. Using the Visual Studio debugger Demo (revit and acad) • Watch window • Variables • Autos • Locals • Watch • Can change variable data at runtime • Can use format specifiers to change the display of data • Step commands

19. Using the Visual Studio debugger • Breakpoint • To set one: • Press F9 • Right Click->Set Breakpoint • Click in the margin • Halts execution at a specific line • Allows visualization of memory state at a given execution state • Step into, step over, step out, run, run to cursor • Right click -> Step into specific

20. Using the Visual Studio debugger Demo (revit) • Breakpoint “types” • Default == break every time • Location • Condition • Hit Count • Filter (Processes and Threads) • For example, break in process 1, but not in 2 • When Hit (Uses trace points) • Print Message: myPtr Val: $(myPtr) • Run macro • Edit Labels

21. Using the Visual Studio debugger Demo (acad) • Other useful windows • Call Stack • Output • Remember to turn off output you do not want to see. • Can redirectto Immediate window. • Modules • Registers • Processes (useful in multi process apps/COM/etc.) • Threads • Memory

22. Using the Visual Studio debugger – tips/tricks/demo demo • Use the breakpoint window • Helps you to see what break points and where • You can also directly set breakpoints there • Use labels with your break points • Disable, rather than delete breakpoints • Call Stack break point • Use Step into specific • Run to Cursor (temp break point) • Drag the execution pointer to another line • Change values in the watch window • Use the find tool in other windows (ie. it can help in output) • Turn on/off output that may or may not be interesting for you debugging session.

23. Symbols • PDB files are the key • Contains the debugging information • Symbols also generated in “release” mode. • Optimization can cause “tricky” debugging • This is how it is possible to debug production software, using pdbs. • AutoCAD and 3ds Max now have public symbol servers! • http://symbols.autodesk.com/symbols

24. Symbols • When using symbols, versions MUST MATCH • internally a GUID is present and must match • Symbol servers simplify this task, but there are more “unknowns” when it doesn’t work • Likely we have not uploaded proper symbols, so let us know • Consider setting up a Symbol server internally for your own public builds • Great Blog article here about symbols: • http://www.wintellect.com/CS/blogs/jrobbins/archive/2009/05/11/pdb-files-what-every-developer-must-know.aspx

25. Managed debugging demo • Managed APIs are often wrappers around native C++ APIs • This can sometimes cause strange debugging results • Managed debugger shares many of the same features • Revit • Mixed-Mode debugging can be very useful • AutoCAD • 3ds Max

26. Customer Error Report (CER) • CER = Customer Error Report. • Key Information Collected by CER • Mini-dump files • Snapshot of the memory • Applications Counters

27. Key Information Collected by CER • System Information • Hardware information • Computer manufacturer • Amount of RAM installed • Number of processors • Video card model • Video card driver version • Configured video resolution • Amount of video ram • Operating System • Computer Name

28. CER debugging – How to debug the minidump Make sure to have the EXACT production install indicated in the CER data Use the EXACT matching debug symbols if you have them devenv <minidump>.dmp

29. Code Structure tools • Intellisense • Code Model • Dynamic help when coding and debugging • Rewritten completely for VS2010 using an actual database (instead of NCB file) • VS2010 Ultimate has an Architecture feature • UML diagrams built in • Dependency graph • Visual Assist • Spell checker! • Plus many other useful helpers

30. Other useful tools • Dependency Walker (depends) • http://dependencywalker.com/ • SysInternals stuff • http://technet.microsoft.com/en-us/sysinternals/default.aspx • Reflector (for .NET Assemblies) • http://reflector.red-gate.com/download.aspx • (no longer free ) • WinDbg • http://msdn.microsoft.com/en-us/windows/hardware/gg463009.aspx

31. How to Debug Autodesk Plug-ins? – Summary • Coding Techniques • Additional Application specific options • Visually Inspect the Code • Use VS debugging tools • CER mini dump files

32. Developing Autodesk plug-ins • Autodesk has pages for most of the products that have APIs • The website entry for developing on a specific product is typically: • http://www.autodesk.com/develop<product name> • http://www.autodesk.com/develop3dsmax • http://www.autodesk.com/developmaya • http://www.autodesk.com/developmotionbuilder • http://www.autodesk.com/developfbx • http://www.autodesk.com/developautocad • http://www.autodesk.com/developrevit • http://www.autodesk.com/developinventor

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34. Questions? Why do programmers always mix up Halloween and Christmas? Because Oct 31 equals Dec 25! Feel free to contact me later