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[wxWidgets.git] / docs / latex / wx / stackwalker.tex

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%% Name:        stackwalker.tex
%% Purpose:     wxStackWalker documentation
%% Author:      Vadim Zeitlin
%% Created:     2005-01-19
%% RCS-ID:      $Id$
%% Copyright:   (c) 2005 Vadim Zeitlin
%% License:     wxWindows license
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\section{\class{wxStackWalker}}\label{wxstackwalker}

wxStackWalker allows an application to enumerate, or walk, the stack frames (the function callstack).
It is mostly useful in only two situations:
inside \helpref{wxApp::OnFatalException}{wxapponfatalexception} function to
programmatically get the location of the crash and, in debug builds, in
\helpref{wxApp::OnAssertFailure}{wxapponassertfailure} to report the caller of the failed
assert.

wxStackWalker works by repeatedly calling
the \helpref{OnStackFrame}{wxstackwalkeronstackframe} method for each frame in the
stack, so to use it you must derive your own class from it and override this
method.

This class will not return anything except raw stack frame addresses if the
debug information is not available. Under Win32 this means that the PDB file
matching the program being executed should be present. Note that if you use
Microsoft Visual C++ compiler, you can create PDB files even for the programs
built in release mode and it doesn't affect the program size (at least if you
don't forget to add \texttt{/opt:ref} option which is suppressed by using
\texttt{/debug} linker option by default but should be always enabled for
release builds). Under Unix, you need to compile your program with debugging
information (usually using \texttt{-g} compiler and linker options) to get the
file and line numbers information, however function names should be available
even without it. Of course, all this is only true if you build using a recent
enough version of GNU libc which provides the \texttt{backtrace()} function
needed to walk the stack.

\helpref{debugging overview}{debuggingoverview} for how to make it available.

\wxheading{Derived from}

No base class

\wxheading{Include files}

<wx/stackwalk.h>

\wxheading{Library}

\helpref{wxBase}{librarieslist}

Only available if \texttt{wxUSE\_STACKWALKER} is $1$, currently only
implemented for Win32 and Unix versions using recent version of GNU libc.

\wxheading{See also}

\helpref{wxStackFrame}{wxstackframe}


\latexignore{\rtfignore{\wxheading{Members}}}


\membersection{wxStackWalker::wxStackWalker}\label{wxstackwalkerwxstackwalker}

\func{}{wxStackWalker}{\void}

Constructor does nothing, use \helpref{Walk()}{wxstackwalkerwalk} to walk the
stack.


\membersection{wxStackWalker::\destruct{wxStackWalker}}\label{wxstackwalkerdtor}

\func{}{\destruct{wxStackWalker}}{\void}

Destructor does nothing neither but should be virtual as this class is used as
a base one.


\membersection{wxStackWalker::OnStackFrame}\label{wxstackwalkeronstackframe}

\func{void}{OnStackFrame}{\param{const wxStackFrame\& }{frame}}

This function must be overrided to process the given frame.


\membersection{wxStackWalker::Walk}\label{wxstackwalkerwalk}

\func{void}{Walk}{\param{size\_t }{skip = 1}, \param{size\_t }{maxDepth = 200}}

Enumerate stack frames from the current location, skipping the initial
number of them (this can be useful when Walk() is called from some known
location and you don't want to see the first few frames anyhow; also
notice that Walk() frame itself is not included if skip $\ge 1$).

Up to \arg{maxDepth} frames are walked from the innermost to the outermost one.


\membersection{wxStackWalker::WalkFromException}\label{wxstackwalkerwalkfromexception}

\func{void}{WalkFromException}{\param{size\_t }{maxDepth = 200}}

Enumerate stack frames from the location of uncaught exception.
This method can only be called from
\helpref{wxApp::OnFatalException()}{wxapponfatalexception}.

Up to \arg{maxDepth} frames are walked from the innermost to the outermost one.