cpython/Doc/library/pdb.rst

363 lines
14 KiB
ReStructuredText
Raw Normal View History

2007-08-15 11:28:01 -03:00
.. _debugger:
:mod:`pdb` --- The Python Debugger
==================================
2007-08-15 11:28:01 -03:00
.. module:: pdb
:synopsis: The Python debugger for interactive interpreters.
.. index:: single: debugging
The module :mod:`pdb` defines an interactive source code debugger for Python
programs. It supports setting (conditional) breakpoints and single stepping at
the source line level, inspection of stack frames, source code listing, and
evaluation of arbitrary Python code in the context of any stack frame. It also
supports post-mortem debugging and can be called under program control.
.. index::
single: Pdb (class in pdb)
module: bdb
module: cmd
The debugger is extensible --- it is actually defined as the class :class:`Pdb`.
This is currently undocumented but easily understood by reading the source. The
Merged revisions 78859-78860,78952,79168-79169,79173,79176,79178-79179,79181,79184-79185,79192,79212 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r78859 | georg.brandl | 2010-03-12 10:57:43 +0100 (Fr, 12 Mär 2010) | 1 line Get rid of backticks. ........ r78860 | georg.brandl | 2010-03-12 11:02:03 +0100 (Fr, 12 Mär 2010) | 1 line Fix warnings from "make check". ........ r78952 | georg.brandl | 2010-03-14 10:55:08 +0100 (So, 14 Mär 2010) | 1 line #8137: add iso-8859-16 to the standard encodings table. ........ r79168 | georg.brandl | 2010-03-21 10:01:27 +0100 (So, 21 Mär 2010) | 1 line Fix some issues found by Jacques Ducasse on the docs list. ........ r79169 | georg.brandl | 2010-03-21 10:02:01 +0100 (So, 21 Mär 2010) | 1 line Remove the "built-in objects" file. It only contained two paragraphs of which only one contained useful information, which belongs in the ref manual however. ........ r79173 | georg.brandl | 2010-03-21 10:09:38 +0100 (So, 21 Mär 2010) | 1 line Document that GzipFile supports iteration. ........ r79176 | georg.brandl | 2010-03-21 10:17:41 +0100 (So, 21 Mär 2010) | 1 line Introduce copy by slicing, used in later chapters. ........ r79178 | georg.brandl | 2010-03-21 10:28:16 +0100 (So, 21 Mär 2010) | 1 line Clarify that for shell=True, the shell PID will be the child PID. ........ r79179 | georg.brandl | 2010-03-21 10:37:54 +0100 (So, 21 Mär 2010) | 1 line Mention inefficiency of lists as queues, add link to collections.deque discussion. ........ r79181 | georg.brandl | 2010-03-21 10:51:16 +0100 (So, 21 Mär 2010) | 1 line Update os.kill() emulation example for Windows to use ctypes. ........ r79184 | georg.brandl | 2010-03-21 10:58:36 +0100 (So, 21 Mär 2010) | 1 line Update text for newest US DST regulation. The sample file already has the calculation right. ........ r79185 | georg.brandl | 2010-03-21 11:02:47 +0100 (So, 21 Mär 2010) | 1 line Include structmember.h correctly. ........ r79192 | georg.brandl | 2010-03-21 12:50:58 +0100 (So, 21 Mär 2010) | 1 line Remove leftover word. ........ r79212 | georg.brandl | 2010-03-21 20:01:38 +0100 (So, 21 Mär 2010) | 1 line Fix plural. ........
2010-03-21 16:34:26 -03:00
extension interface uses the modules :mod:`bdb` and :mod:`cmd`.
2007-08-15 11:28:01 -03:00
The debugger's prompt is ``(Pdb)``. Typical usage to run a program under control
of the debugger is::
>>> import pdb
>>> import mymodule
>>> pdb.run('mymodule.test()')
> <string>(0)?()
(Pdb) continue
> <string>(1)?()
(Pdb) continue
NameError: 'spam'
> <string>(1)?()
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
(Pdb)
2007-08-15 11:28:01 -03:00
:file:`pdb.py` can also be invoked as a script to debug other scripts. For
example::
python -m pdb myscript.py
When invoked as a script, pdb will automatically enter post-mortem debugging if
the program being debugged exits abnormally. After post-mortem debugging (or
after normal exit of the program), pdb will restart the program. Automatic
restarting preserves pdb's state (such as breakpoints) and in most cases is more
useful than quitting the debugger upon program's exit.
.. versionadded:: 2.4
Restarting post-mortem behavior added.
Merged revisions 74861-74863,74876,74896,74930,74933,74952-74953,75015,75019,75260-75263,75265-75266,75289 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74861 | benjamin.peterson | 2009-09-17 05:18:28 +0200 (Do, 17 Sep 2009) | 1 line pep 8 defaults ........ r74862 | brett.cannon | 2009-09-17 05:24:45 +0200 (Do, 17 Sep 2009) | 1 line Note in the intro to Extending... that ctypes can be a simpler, more portable solution than custom C code. ........ r74863 | benjamin.peterson | 2009-09-17 05:27:33 +0200 (Do, 17 Sep 2009) | 1 line rationalize a bit ........ r74876 | georg.brandl | 2009-09-17 18:15:53 +0200 (Do, 17 Sep 2009) | 1 line #6932: remove paragraph that advises relying on __del__ being called. ........ r74896 | georg.brandl | 2009-09-18 09:22:41 +0200 (Fr, 18 Sep 2009) | 1 line #6936: for interactive use, quit() is just fine. ........ r74930 | georg.brandl | 2009-09-18 23:21:41 +0200 (Fr, 18 Sep 2009) | 1 line #6925: rewrite docs for locals() and vars() a bit. ........ r74933 | georg.brandl | 2009-09-18 23:35:59 +0200 (Fr, 18 Sep 2009) | 1 line #6930: clarify description about byteorder handling in UTF decoder routines. ........ r74952 | georg.brandl | 2009-09-19 12:42:34 +0200 (Sa, 19 Sep 2009) | 1 line #6946: fix duplicate index entries for datetime classes. ........ r74953 | georg.brandl | 2009-09-19 14:04:16 +0200 (Sa, 19 Sep 2009) | 1 line Fix references to threading.enumerate(). ........ r75015 | georg.brandl | 2009-09-22 12:55:08 +0200 (Di, 22 Sep 2009) | 1 line Fix encoding name. ........ r75019 | vinay.sajip | 2009-09-22 19:23:41 +0200 (Di, 22 Sep 2009) | 1 line Fixed a typo, and added sections on optimization and using arbitrary objects as messages. ........ r75260 | andrew.kuchling | 2009-10-05 23:24:20 +0200 (Mo, 05 Okt 2009) | 1 line Wording fix ........ r75261 | andrew.kuchling | 2009-10-05 23:24:35 +0200 (Mo, 05 Okt 2009) | 1 line Fix narkup ........ r75262 | andrew.kuchling | 2009-10-05 23:25:03 +0200 (Mo, 05 Okt 2009) | 1 line Document 'skip' parameter to constructor ........ r75263 | andrew.kuchling | 2009-10-05 23:25:35 +0200 (Mo, 05 Okt 2009) | 1 line Note side benefit of socket.create_connection() ........ r75265 | andrew.kuchling | 2009-10-06 00:31:11 +0200 (Di, 06 Okt 2009) | 1 line Reword sentence ........ r75266 | andrew.kuchling | 2009-10-06 00:32:48 +0200 (Di, 06 Okt 2009) | 1 line Use standard comma punctuation; reword some sentences in the docs ........ r75289 | mark.dickinson | 2009-10-08 22:02:25 +0200 (Do, 08 Okt 2009) | 2 lines Issue #7051: Clarify behaviour of 'g' and 'G'-style formatting. ........
2009-10-27 11:59:26 -03:00
The typical usage to break into the debugger from a running program is to
insert ::
import pdb; pdb.set_trace()
at the location you want to break into the debugger. You can then step through
the code following this statement, and continue running without the debugger using
the ``c`` command.
The typical usage to inspect a crashed program is::
2007-08-15 11:28:01 -03:00
>>> import pdb
>>> import mymodule
>>> mymodule.test()
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "./mymodule.py", line 4, in test
test2()
File "./mymodule.py", line 3, in test2
print spam
NameError: spam
>>> pdb.pm()
> ./mymodule.py(3)test2()
-> print spam
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
(Pdb)
2007-08-15 11:28:01 -03:00
The module defines the following functions; each enters the debugger in a
slightly different way:
.. function:: run(statement[, globals[, locals]])
Execute the *statement* (given as a string) under debugger control. The
debugger prompt appears before any code is executed; you can set breakpoints and
type ``continue``, or you can step through the statement using ``step`` or
``next`` (all these commands are explained below). The optional *globals* and
*locals* arguments specify the environment in which the code is executed; by
default the dictionary of the module :mod:`__main__` is used. (See the
explanation of the :keyword:`exec` statement or the :func:`eval` built-in
function.)
.. function:: runeval(expression[, globals[, locals]])
Evaluate the *expression* (given as a string) under debugger control. When
:func:`runeval` returns, it returns the value of the expression. Otherwise this
function is similar to :func:`run`.
.. function:: runcall(function[, argument, ...])
Call the *function* (a function or method object, not a string) with the given
arguments. When :func:`runcall` returns, it returns whatever the function call
returned. The debugger prompt appears as soon as the function is entered.
.. function:: set_trace()
Enter the debugger at the calling stack frame. This is useful to hard-code a
breakpoint at a given point in a program, even if the code is not otherwise
being debugged (e.g. when an assertion fails).
.. function:: post_mortem([traceback])
2007-08-15 11:28:01 -03:00
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
2009-01-03 17:55:17 -04:00
Enter post-mortem debugging of the given *traceback* object. If no
*traceback* is given, it uses the one of the exception that is currently
being handled (an exception must be being handled if the default is to be
used).
2007-08-15 11:28:01 -03:00
.. function:: pm()
Enter post-mortem debugging of the traceback found in ``sys.last_traceback``.
.. _debugger-commands:
Debugger Commands
=================
The debugger recognizes the following commands. Most commands can be
abbreviated to one or two letters; e.g. ``h(elp)`` means that either ``h`` or
``help`` can be used to enter the help command (but not ``he`` or ``hel``, nor
``H`` or ``Help`` or ``HELP``). Arguments to commands must be separated by
whitespace (spaces or tabs). Optional arguments are enclosed in square brackets
(``[]``) in the command syntax; the square brackets must not be typed.
Alternatives in the command syntax are separated by a vertical bar (``|``).
Entering a blank line repeats the last command entered. Exception: if the last
command was a ``list`` command, the next 11 lines are listed.
Commands that the debugger doesn't recognize are assumed to be Python statements
and are executed in the context of the program being debugged. Python
statements can also be prefixed with an exclamation point (``!``). This is a
powerful way to inspect the program being debugged; it is even possible to
change a variable or call a function. When an exception occurs in such a
statement, the exception name is printed but the debugger's state is not
changed.
Multiple commands may be entered on a single line, separated by ``;;``. (A
single ``;`` is not used as it is the separator for multiple commands in a line
that is passed to the Python parser.) No intelligence is applied to separating
the commands; the input is split at the first ``;;`` pair, even if it is in the
middle of a quoted string.
The debugger supports aliases. Aliases can have parameters which allows one a
certain level of adaptability to the context under examination.
.. index::
pair: .pdbrc; file
triple: debugger; configuration; file
If a file :file:`.pdbrc` exists in the user's home directory or in the current
directory, it is read in and executed as if it had been typed at the debugger
prompt. This is particularly useful for aliases. If both files exist, the one
in the home directory is read first and aliases defined there can be overridden
by the local file.
h(elp) [*command*]
Without argument, print the list of available commands. With a *command* as
argument, print help about that command. ``help pdb`` displays the full
documentation file; if the environment variable :envvar:`PAGER` is defined, the
file is piped through that command instead. Since the *command* argument must
be an identifier, ``help exec`` must be entered to get help on the ``!``
command.
w(here)
Print a stack trace, with the most recent frame at the bottom. An arrow
indicates the current frame, which determines the context of most commands.
d(own)
Move the current frame one level down in the stack trace (to a newer frame).
u(p)
Move the current frame one level up in the stack trace (to an older frame).
2007-08-18 03:05:56 -03:00
b(reak) [[*filename*:]\ *lineno* | *function*\ [, *condition*]]
2007-08-15 11:28:01 -03:00
With a *lineno* argument, set a break there in the current file. With a
*function* argument, set a break at the first executable statement within that
function. The line number may be prefixed with a filename and a colon, to
specify a breakpoint in another file (probably one that hasn't been loaded yet).
The file is searched on ``sys.path``. Note that each breakpoint is assigned a
number to which all the other breakpoint commands refer.
If a second argument is present, it is an expression which must evaluate to true
before the breakpoint is honored.
Without argument, list all breaks, including for each breakpoint, the number of
times that breakpoint has been hit, the current ignore count, and the associated
condition if any.
2007-08-18 03:05:56 -03:00
tbreak [[*filename*:]\ *lineno* | *function*\ [, *condition*]]
2007-08-15 11:28:01 -03:00
Temporary breakpoint, which is removed automatically when it is first hit. The
arguments are the same as break.
cl(ear) [*bpnumber* [*bpnumber ...*]]
With a space separated list of breakpoint numbers, clear those breakpoints.
Without argument, clear all breaks (but first ask confirmation).
disable [*bpnumber* [*bpnumber ...*]]
Disables the breakpoints given as a space separated list of breakpoint numbers.
Disabling a breakpoint means it cannot cause the program to stop execution, but
unlike clearing a breakpoint, it remains in the list of breakpoints and can be
(re-)enabled.
enable [*bpnumber* [*bpnumber ...*]]
Enables the breakpoints specified.
ignore *bpnumber* [*count*]
Sets the ignore count for the given breakpoint number. If count is omitted, the
ignore count is set to 0. A breakpoint becomes active when the ignore count is
zero. When non-zero, the count is decremented each time the breakpoint is
reached and the breakpoint is not disabled and any associated condition
evaluates to true.
condition *bpnumber* [*condition*]
Condition is an expression which must evaluate to true before the breakpoint is
honored. If condition is absent, any existing condition is removed; i.e., the
breakpoint is made unconditional.
commands [*bpnumber*]
Specify a list of commands for breakpoint number *bpnumber*. The commands
themselves appear on the following lines. Type a line containing just 'end' to
terminate the commands. An example::
(Pdb) commands 1
(com) print some_variable
(com) end
(Pdb)
To remove all commands from a breakpoint, type commands and follow it
immediately with end; that is, give no commands.
With no *bpnumber* argument, commands refers to the last breakpoint set.
You can use breakpoint commands to start your program up again. Simply use the
continue command, or step, or any other command that resumes execution.
Specifying any command resuming execution (currently continue, step, next,
return, jump, quit and their abbreviations) terminates the command list (as if
that command was immediately followed by end). This is because any time you
resume execution (even with a simple next or step), you may encounter another
2007-08-15 11:28:01 -03:00
breakpoint--which could have its own command list, leading to ambiguities about
which list to execute.
If you use the 'silent' command in the command list, the usual message about
stopping at a breakpoint is not printed. This may be desirable for breakpoints
that are to print a specific message and then continue. If none of the other
commands print anything, you see no sign that the breakpoint was reached.
.. versionadded:: 2.5
s(tep)
Execute the current line, stop at the first possible occasion (either in a
function that is called or on the next line in the current function).
n(ext)
Continue execution until the next line in the current function is reached or it
returns. (The difference between ``next`` and ``step`` is that ``step`` stops
inside a called function, while ``next`` executes called functions at (nearly)
full speed, only stopping at the next line in the current function.)
2008-05-11 11:13:25 -03:00
unt(il)
Continue execution until the line with the line number greater than the
2008-05-11 11:17:13 -03:00
current one is reached or when returning from current frame.
2008-05-11 11:13:25 -03:00
.. versionadded:: 2.6
2007-08-15 11:28:01 -03:00
r(eturn)
Continue execution until the current function returns.
c(ont(inue))
Continue execution, only stop when a breakpoint is encountered.
j(ump) *lineno*
Set the next line that will be executed. Only available in the bottom-most
frame. This lets you jump back and execute code again, or jump forward to skip
code that you don't want to run.
It should be noted that not all jumps are allowed --- for instance it is not
possible to jump into the middle of a :keyword:`for` loop or out of a
:keyword:`finally` clause.
2007-08-18 03:05:56 -03:00
l(ist) [*first*\ [, *last*]]
2007-08-15 11:28:01 -03:00
List source code for the current file. Without arguments, list 11 lines around
the current line or continue the previous listing. With one argument, list 11
lines around at that line. With two arguments, list the given range; if the
second argument is less than the first, it is interpreted as a count.
a(rgs)
Print the argument list of the current function.
p *expression*
Evaluate the *expression* in the current context and print its value.
.. note::
``print`` can also be used, but is not a debugger command --- this executes the
Python :keyword:`print` statement.
pp *expression*
Like the ``p`` command, except the value of the expression is pretty-printed
using the :mod:`pprint` module.
alias [*name* [command]]
Creates an alias called *name* that executes *command*. The command must *not*
be enclosed in quotes. Replaceable parameters can be indicated by ``%1``,
``%2``, and so on, while ``%*`` is replaced by all the parameters. If no
command is given, the current alias for *name* is shown. If no arguments are
given, all aliases are listed.
Aliases may be nested and can contain anything that can be legally typed at the
pdb prompt. Note that internal pdb commands *can* be overridden by aliases.
Such a command is then hidden until the alias is removed. Aliasing is
recursively applied to the first word of the command line; all other words in
the line are left alone.
As an example, here are two useful aliases (especially when placed in the
:file:`.pdbrc` file)::
#Print instance variables (usage "pi classInst")
alias pi for k in %1.__dict__.keys(): print "%1.",k,"=",%1.__dict__[k]
#Print instance variables in self
alias ps pi self
unalias *name*
Deletes the specified alias.
2007-08-18 03:05:56 -03:00
[!]\ *statement*
2007-08-15 11:28:01 -03:00
Execute the (one-line) *statement* in the context of the current stack frame.
The exclamation point can be omitted unless the first word of the statement
resembles a debugger command. To set a global variable, you can prefix the
assignment command with a ``global`` command on the same line, e.g.::
(Pdb) global list_options; list_options = ['-l']
(Pdb)
run [*args* ...]
Restart the debugged Python program. If an argument is supplied, it is split
2007-08-15 11:28:01 -03:00
with "shlex" and the result is used as the new sys.argv. History, breakpoints,
actions and debugger options are preserved. "restart" is an alias for "run".
.. versionadded:: 2.6
q(uit)
Quit from the debugger. The program being executed is aborted.