'''Debugging''' is the of process diagnosing and correcting unexpected behaviour
of programs.



** See Also **

   [Category Debugging]:    

   [IDE]:   many of which provide debugging functionality along with other features

   [Profiling Tcl]:   

   [Static syntax analysis]:   



** Concepts **

   [call graph]:   



** Tools for Dynamic Analysis **

   [a basic debugger]:   

   [a debugger with syntax highlighting using ctext]:   

   [A minimal debugger]:   

   [atkdebugger]:   A patch for Tcl 8.5 is available at the website

   [d: A handy little debugging proc]:   by [Ed Suominen], for development of PRIVARIA [http://www.privaria.org/], an end-user TCL app with a lot going on inside.

   [a minimal debugger]:   implements breakpoints, allowing to run any Tcl command, including inspecting and setting the local variables...

   [Errx]:   a mixed debug-message / stack backtrace introspection "puts"

   [gdb]:   

   [Guarded proc]:   [RS]: monitors or prevents redefining an existing proc


   [Tkinspect]:   a stand alone application that queries a running Tk application and then displays its state.  This allows you to display current variable values and modify procs or variables. A [Tix]-enabled version of it is in [TixInspect]. The [Tcl Dev Kit] provides an enhanced version of TkInspect since release 2.5.

   [TkCon]:   [http://www.purl.org/net/hobbs/tcl/script/tkcon/]:  by [JH%|%Jeff Hobbs%|%]. A great way to interact with a running Tcl/Tk application. It can be attached to any Tcl/Tk interpreter or namespace and allows any modification. This application comes bundled with [ActiveTcl] and therefore also with [Tcl Dev Kit].  Sports facilities such as [http://tkcon.sourceforge.net/docs/idebug.html%|%idedebug%|%] and [http://tkcon.sourceforge.net/docs/observe.html%|%observe%|%], which provide sophisticated breakpoint and tracing facilities, and '''hot errors''',  which displays the source of the proc in dig-down style

   [INSPECT app]:   

   [valgrind]:   

   [Electric Fence]:   

   [PED]:   

   [RamDebugger]:   

   [Yet another Tcl debugger]:   

   [Tagma Debugger]:   A rewrite of Yet another Tcl debugger.

   [TclPro]:   a popular open-source debugger originally sold by [Scriptics]

   [Tuba]:   providing source code viewing as you step thru the code, breakpoints on specific lines and procs, and ability to set watchpoints on variables

   [ftp://ftp.procplace.com/pub/tcl/sorted/packages-7.6/devel/%|%TDebug%|%]:   a Tk based debugger that is sourced into your script.  Works conceptually like the emacs-lisp debugger.  An updated version of it is in [TixDebug].

   The 'tracecommand' extension:   based on a patch [ftp://ftp.ucsd.edu/pub/alpha/tcl/extensions/trace.c] [[does [Vince Darley] have a more recent version of this?]] to the Tcl core, is available from the scriptics bug database [[we need a URL here]].  It can be used to dump before/after command+argument+result evaluations both globally or only inside a given command or procedure.  It is similar to the 'trace dump' facility available in the Tcl-scripted MacOS editor 'Alpha'.

   [http://www.fridu.com/Html/jTcl.html%|%jTcl%|%]:   a Java-like object interface which provides debugging facilities.  [escargo]  2004-02-04: dead link. 



** Publications **

   [http://computerworld.com/newsletter/0%2C4902%2C77375%2C0.html?nlid=APP%|%A Debugging Primer%|%]:   an excerpt [Debugging: The 9 Indispensable Rules For Finding Even the Most Elusive Software and Hardware Problems, David J. Agans]

   [How to be a Programmer: A Short, Comprehensive, and Personal Summary, Robert L. Read, 2002]:   [PYK] 2012-12: a quick glance-through indicates that this is worth the read.  Others have received it positively as well.



** See Also **

   [C compiled image processing on an interactive Bwise canvas]:   

   [Commonly encountered problems in Tcl]:   

   [Debugging Aid For Production Code]:   

   [Debugging Expect programs]:   

   [debug with trace]:   

   [Dynamic Debugger]:   a strange breed.  For whatever reason, many programmers are either unfamilar or dissatisfied with most of the products in this category.

   [Debugging via introspection]:   

   [Effective ways to request help with Tcl-related problems]:   

   [Favorite debugging techniques applicable to Tcl]:   

   [Help! My Tcl application just crashed!]:   

   [How to debug memory faults in Tcl and extensions]:   

   [Leak Hunt (C level)]:   

   [List the call stack]:   

   [Memory introspection]:   important when trying to find bugs going into the C-level, especially hard to pin-down memory trouble

   [regular expression debugging tips]:   

   [Static syntax analysis]:   Static code checkers are tools which read your Tcl code and attempt to identify either real, or potential, problems.  This is similar to the Unix ''lint'' command.

   [Steppin' out]:   uses Tcl's own command tracing

   [traceproc helper]:   specify a list of commands to monitor, and see the actual arguments passed to the commands when they are run, as well as the result.

   [traceback]:   

   [what debugging tools are available to a Tcl programmer]:   

   [Whole-Script Tracing]:   


** Components with Debugging Features **

   [Tcl%|%Tcl itself]:   provides enhanced command tracing since release 8.4 (See [TIP] #62). Example of usage is at [Steppin' out].

   [BLT]:   comes with several useful debugging commands.

   [TclX]:   comes with commands for profiling and debugging facilities, for example [cmdtrace].

   [http://www.csua.berkeley.edu/%7Esls/woa/distrib/%|%SNTL%|%]:   includes a debugging message system.

   [Source Navigator]:   an IDE with code comprehension features.  It is written in Tcl/Tk/itcl, but allows you to understand code written in a wide variety of languages.


** Projects **

   [GSoC Idea: Debugging tools for NRE]:   




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