Difference between revisions of "Windows/Debugging"

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=General Hints=
#REDIRECT [[Guidelines and HOWTOs/Debugging/MS Windows]]
==Debugging with DebugView==
Debug messages (logs) generated by kDebug() and kWarning() are not visible on MS Windows unless application is compiled in so-called CONSOLE subsystem. To show these messages also in WINDOWS subsystem, you can use DebugView tool, coming from SysInternals (currently acquired by Microsoft). The tool offers searching in logs, filtering and saving them to file.
→ [http://www.microsoft.com/technet/sysinternals/utilities/debugview.mspx More informations]
==Debugging kioslaves==
kioslaves on windows are started by klauncher (or kio) as separate kioslave processes. The kioslave executable then loads the related kioslave dll dynamically.
=== Using KDE_SLAVE_DEBUG_WAIT variable ===
To debug kioslaves:
#Set the KDE_SLAVE_DEBUG_WAIT environment variable in a current cmd.exe shell to the name of the kioslave's protocol (the first parameter of KIO::SlaveBase() constructor), e.g.<pre>set KDE_SLAVE_DEBUG_WAIT=file</pre>
#Terminate <tt>klauncher</tt> process so it can be restarted.
#Any application you want to debug at kioslave level have to be executed within the scope of the current environment (cmd.exe), what also means that if you want to use development environment, you have to do taht in the environment as well, e.g. for MSVC Express, by typing <tt>vcepress</tt>.
If the kioslave is requested the next time, a debugger will be started and attached to the kioslave process immediatly before the kioslave's kdemain() function.
On mingw platform gdb is launched and connected to the kioslave process. On msvc platforms the currently installed just-in-time debugger is used. This may be msvc's IDE or the [http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx windbg debugger].  The latter could be set as jit-debugger by running 'windbg -I' command.
=== Using KDE_SLAVE_DEBUG_POPUP variable ===
Alternatively, you can set <tt>KDE_SLAVE_DEBUG_POPUP</tt> variable instead of <tt>KDE_SLAVE_DEBUG_WAIT</tt>. This will display a native message box so developer you can attach the debugger to the KIO slave process and click OK. No DebugBreak() is invoked. Just click OK without attaching to continue using the KIO slave without debugging.
=== Notes ===
*You can set, say, the variable to 'file' for the kio_file slave, '''but''' set it to 'smtps' for the kio_smtp is you want to debug smtp protocol secured with SSL.
*(Vista only): ''kioslave.exe has stopped working'' message dialog can appear instead of offer for starting the debugger. Reason: Just-In-Time (JIT) Debugging of an elevated process will fail ([http://msdn2.microsoft.com/en-us/vstudio/aa964140.aspx#question20a msdn link]) apparently for security reasons. Either:
**Use <tt>KDE_SLAVE_DEBUG_POPUP</tt> instead of <tt>KDE_SLAVE_DEBUG_WAIT</tt>. See the "Using KDE_SLAVE_DEBUG_POPUP variable" above for more info/
**(not possible under msvc 2005): start applications and klauncher without administration permissions or attach the debugger manually before the debugger catches unhandled exceptions or an user-defined breakpoint (DebugBreak()).
*You may inspect kioslave sources [http://lxr.kde.org/source/KDE/kdelibs/kinit/kioslave.cpp] for more informations.
== checking dependency of shared libraries ==
[http://www.dependencywalker.com/ Dependency Walker] is a free utility that scans any 32-bit or 64-bit Windows module (exe, dll, ocx, sys, etc.) and builds a hierarchical tree diagram of all dependent modules.
= MS Visual Studio hints =
== Using MS Visual Studio environment for just debugging ==
Let's assume you're using command line tools (typically CMake) and want to use MS Visual Studio environment for just debugging. You don't need to create msvc project for your KDE application to be able to start debugging.
* compile and working executable version of your appliation (compiled in debug mode)
* run msvc environment
* execute ''File->Open project''
* pick your exe file in the file window
* you can set command line arguments as usual, by pick ''Project->...Properties'' command and enter all of them it in ''Command Arguments'' field
* if you have libraries placed in other directories than your application's .exe file, and you want to step into these libraries' source code while debugging, pick ''Project->...Properties'' command and enter paths to these directories in ''Symbol Path'' field
* hit F5 to run the application start the application or F10 to start step by step
* all debugging functions like setting breakpoints will be available, so you can open source code in the integrated editor and press F9 where needed
* you can even edit your source code but to compile it, do it with your external, command line tools. You cannot compile the application in the msvc environment because you have not defined a project file
* before compiling your application, stop debugging session to unlock binaries; no need to close msvc window
* after compilation you can start debugging again
* on exit you will be asked to save .sln file (so-called ''solution file'') with your debugging session -- do it and you will be able just to click the .sln file to start your debugging again
* it's recommended to save the .sln file in the .exe file directory
* next time you will run msvc environment, you can see name of your application's .sln file in ''File->Recent Projects'' submenu - you can click it to load your debugging session
== Attaching to running application ==
If you have your application is already running, you can attach to it and then start debugging.
* run msvc environment
* execute ''Debug->processes''
* select your from the processes list and click "Attach..."
* msvc environment will load your .sln file if it exists in the same directory as the .exe file, so your breakpoints set in previous session will be active again
* your program will stop on any breakpoint you have set
== One-step attaching to running application ==
You can create a macro that automates the task. See [http://blogs.msdn.com/jimgries/archive/2005/11/30/498264.aspx].
== Memory Values ==
If you are using the debug heap, memory is initialized and cleared with special values. Most interesting values are:
* 0xCDCDCDCD - Allocated in heap, but not initialized
* 0xDDDDDDDD - Released heap memory.
* 0xFDFDFDFD - "NoMansLand" fences automatically placed at boundary of heap memory. Should never be overwritten. If you do overwrite one, you're probably walking off the end of an array.
* 0xCCCCCCCC - Allocated on stack, but not initialized
See also: [http://www.samblackburn.com/wfc/technotes/WTN006.htm]
==How to Not Step Into Functions in the Debugger==
You'll probably want to avoind stepping into lower-level functions like QString constructors or operators while debugging step-by-step. Here's the detailed (unofficial) [http://blogs.msdn.com/andypennell/archive/2004/02/06/69004.aspx instruction] for various msvc versions.
==Enable automatic expanding of Qt data structures==
From the msvc docs: "While debugging, Data Tips and items in the Watch and Variable windows are automatically expanded to show their most important elements. The expansion follows the format given by the rules in this file. You can add rules for your types or change the predefined rules." ([http://www.thedatafarm.com/blog/content/binary/datatips2.jpg example screen])
MSVC 2005: To add support for expanding Qt data structures like QString of QRect, edit {msvc_installation_directory}\Common7\Packages\Debugger\autoexp.dat file and paste [[/Automatic expanding of Qt data structures|definitions]] after [AutoExpand] line.
==WINDOWS and CONSOLE subsystems==
CONSOLE subsystem is the one that displays console window (used for standard output and error streams) in addition to application's windows. WINDOWS subsystem redirects standard output and error streams to system debugging subsystem that can be displayed if needed in dbgview or debuggers like msvc.
Hint: To remove CONSOLE subsystem from already built .exe file, type <code>editbin /subsystem:windows file.exe</code>
Note: Qt's qmake syntax supports ''console'' and ''windows'' parameters of the ''CONFIG'' variable, so CONSOLE subsystem can be enabled by specifying <tt>CONFIG += console</tt> in the .pro file, windows subsystem can be enabled with <tt>CONFIG += windows</tt>.
Running a VC++2005 SP1 app on another computer: manifest files are needed. See [http://www.codeproject.com/KB/cpp/vcredists_x86.aspx] and [http://blogs.msdn.com/nikolad/archive/2005/09/02/460368.aspx].
===Note on debug builds===
The hints above are for release builds (or ReleaseWithDebugInfo). Moving Debug versions of binaries to other computers is only allowed (and technicallu possible) if you have Express Edition installed there, as there is no redistributable package for Debug versions provided and even the license disallows distribution of any debug binaries (even your own).
= MinGW debugging hints =
* Dr. Mingw - Just in Time Debugger [http://jrfonseca.planetaclix.pt/projects/gnu-win32/software/drmingw/]
* Debugging Qt programs on Windows [http://lists.trolltech.com/qt-interest/2005-08/thread01124-0.html]
'''''WARNING''''': If you are having crashes when starting applications via gdb beware of certain applications (mostly anti-virus software) that could cause problems like "Embassy Trust Suite", for example. See this [http://www.cygwin.com/ml/cygwin/2007-06/msg00405.html post].
[[Category:MS Windows]]

Latest revision as of 14:58, 18 March 2016

This page was last edited on 18 March 2016, at 14:58. Content is available under Creative Commons License SA 4.0 unless otherwise noted.