© 2011 Autodesk
CP4349 - Debugging Autodesk® Product Plug-ins
Kevin VandecarPrincipal Developer Consulting Engineer – M&E Sparks Autodesk Developer Network
Two bytes meet. The first byte asks, “Are you ill?” The second byte replies, “No, just feeling a bit off.”
© 2011 Autodesk
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: [email protected]
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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.)
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Debugging…
…is fundamentally problem solving
"Intellectuals solve problems, geniuses prevent them." - Albert Einstein
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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 harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge in another.
aka: Autodesk plug-in developers!
What is Debugging?
Autodesk Application
plug-in 1 plug-in 2 plug-in 3
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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
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How to debug?
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.
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.'
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How to debug?
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
Start Debugging! Use the tools you have The debugger itself is not the only
tool!
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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
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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, MAXScript mprintf AutoCAD: acutPrintf, acedAlert Revit: TaskDialogs
Other Debug code statements http://msdn.microsoft.com/en-us/library/ms679303(v=VS.85).aspx
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Coding Techniques
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
demo (acad)
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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)
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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
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Use Debugging Tools – Visual Studio
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
demo
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VS Debug Project settings
Debugger “type” Auto Managed Native Only Mixed-mode (very useful with C++/CLI together with C++)
Edit and Continue (useful especially when learning)
demo
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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!)
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Using the Visual Studio debugger
Watch window Variables
Autos Locals Watch
Can change variable data at runtime Can use format specifiers to change the display of data
Step commands
Demo (revit and acad)
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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
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Using the Visual Studio debugger
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
Demo (revit)
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Using the Visual Studio debugger
Other useful windows Call Stack Output
Remember to turn off output you do not want to see. Can redirect to Immediate window.
Modules Registers Processes (useful in multi process apps/COM/etc.) Threads Memory
Demo (acad)
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Using the Visual Studio debugger – tips/tricks/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. demo
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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
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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
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Managed debugging
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
demo
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Customer Error Report (CER)
CER = Customer Error Report.
Key Information Collected by CER Mini-dump files Snapshot of the memory Applications Counters
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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
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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
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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
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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
© 2011 Autodesk
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
© 2011 Autodesk
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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Questions?
Feel free to contact me later
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