© 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: kevin.vandecar@autodesk.com

© 2011 Autodesk

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

© 2011 Autodesk

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.)

© 2011 Autodesk

Debugging…

…is fundamentally problem solving

"Intellectuals solve problems, geniuses prevent them." - Albert Einstein

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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.'

© 2011 Autodesk

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!

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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)

© 2011 Autodesk

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)

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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!)

© 2011 Autodesk

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)

© 2011 Autodesk

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

© 2011 Autodesk

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)

© 2011 Autodesk

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)

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

Customer Error Report (CER)

CER = Customer Error Report.

Key Information Collected by CER Mini-dump files Snapshot of the memory Applications Counters

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

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

© 2011 Autodesk

Autodesk University Session Feedback Your feedback is very important to Autodesk! You can complete the session

survey on your mobile device, PC, or at a survey station.

Each completed session survey enters you in that day’s drawing for a free AU 2012 pass.

You can help make AU 2012 better!

Complete the AU Conference Survey at a survey station and receive an AU 2011 T-Shirt.

© 2011 Autodesk

Questions?

Feel free to contact me later

Why do programmers always mix up Halloween and Christmas? Because Oct 31 equals Dec 25!