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Debugging
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Overview
========

* To turn on debug code in general insert the following to ``~/.sbclrc``

.. code-block:: lisp

  (sb-ext:restrict-compiler-policy 'debug 3)

* In debugger mode type ``?`` to get a list of available commands


Trace function calls
====================

.. code-block:: lisp

  (trace function)

* To undo

.. code-block:: lisp

  (untrace function)


Step through a function
=======================

* Every function you want to step into must be compiled with debug optimization, insert

.. code-block:: lisp

  (declaim (optimize (debug 3)))

* Now run

.. code-block:: lisp

  (step (function args))

* And use the command ``:step`` to step into NOT ``:next`` note the ``'``!

* With ``source 10`` you can see the source 10 levels (parantheses) deep


Invoke debugger at specific conditions
======================================

.. code-block:: lisp

  (ignore-errors ;Normally, this would suppress debugger entry
   (handler-bind ((error #'invoke-debugger)) ;But this forces debugger entry
     (error "Foo.")))


Breakpoints
===========

* Insert ``(break)`` at the specific code lines


Measure time of code execution
==============================

.. code-block:: lisp

  (time (function args))


Disassemble a function
======================

.. code-block:: lisp

  (disassemble 'format)