cpython/Doc/lib/libexcs.tex
Guido van Rossum cd16bf6404 Merged revisions 55817-55961 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/p3yk

................
  r55837 | guido.van.rossum | 2007-06-08 16:04:42 -0700 (Fri, 08 Jun 2007) | 2 lines

  PEP 3119 -- the abc module.
................
  r55838 | guido.van.rossum | 2007-06-08 17:38:55 -0700 (Fri, 08 Jun 2007) | 2 lines

  Implement part of PEP 3119 -- One Trick Ponies.
................
  r55847 | guido.van.rossum | 2007-06-09 08:28:06 -0700 (Sat, 09 Jun 2007) | 2 lines

  Different way to do one trick ponies, allowing registration (per PEP strawman).
................
  r55849 | guido.van.rossum | 2007-06-09 18:06:38 -0700 (Sat, 09 Jun 2007) | 3 lines

  Make sure that the magic looking for __hash__ (etc.) doesn't apply to
  real subclasses of Hashable.
................
  r55852 | guido.van.rossum | 2007-06-10 08:29:51 -0700 (Sun, 10 Jun 2007) | 2 lines

  Add some more examples, e.g. generators and dict views.
................
  r55853 | guido.van.rossum | 2007-06-10 08:31:59 -0700 (Sun, 10 Jun 2007) | 2 lines

  keys() and items() *are* containers -- just values() isn't.
................
  r55864 | georg.brandl | 2007-06-10 15:29:40 -0700 (Sun, 10 Jun 2007) | 2 lines

  PEP 3127: new octal literals, binary literals.
................
  r55865 | georg.brandl | 2007-06-10 15:31:37 -0700 (Sun, 10 Jun 2007) | 2 lines

  Some octal literal fixes in Tools.
................
  r55866 | georg.brandl | 2007-06-10 15:37:43 -0700 (Sun, 10 Jun 2007) | 2 lines

  Tokenizer changes for PEP 3127.
................
  r55867 | georg.brandl | 2007-06-10 15:37:55 -0700 (Sun, 10 Jun 2007) | 2 lines

  Some docs for PEP 3127.
................
  r55868 | georg.brandl | 2007-06-10 15:44:39 -0700 (Sun, 10 Jun 2007) | 2 lines

  Missed a place in intobject.c. Is that used anymore anyway?
................
  r55871 | neal.norwitz | 2007-06-10 18:31:49 -0700 (Sun, 10 Jun 2007) | 182 lines

  Merged revisions 55729-55868 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r55731 | neal.norwitz | 2007-06-01 00:29:12 -0700 (Fri, 01 Jun 2007) | 7 lines

    SF 1668596/1720897: distutils now copies data files
    even if package_dir is empty.

    This needs to be backported.  I'm too tired tonight.  It would be great
    if someone backports this if the buildbots are ok with it.  Otherwise,
    I will try to get to it tomorrow.
  ........
    r55732 | georg.brandl | 2007-06-01 04:33:33 -0700 (Fri, 01 Jun 2007) | 2 lines

    Bug #1722484: remove docstrings again when running with -OO.
  ........
    r55735 | georg.brandl | 2007-06-01 12:20:27 -0700 (Fri, 01 Jun 2007) | 2 lines

    Fix wrong issue number.
  ........
    r55739 | brett.cannon | 2007-06-01 20:02:29 -0700 (Fri, 01 Jun 2007) | 3 lines

    Have configure raise an error when building on AtheOS.  Code specific to AtheOS
    will be removed in Python 2.7.
  ........
    r55746 | neal.norwitz | 2007-06-02 11:33:53 -0700 (Sat, 02 Jun 2007) | 1 line

    Update expected birthday of 2.6
  ........
    r55751 | neal.norwitz | 2007-06-03 13:32:50 -0700 (Sun, 03 Jun 2007) | 10 lines

    Backout the original 'fix' to 1721309 which had no effect.
    Different versions of Berkeley DB handle this differently.
    The comments and bug report should have the details.  Memory is allocated
    in 4.4 (and presumably earlier), but not in 4.5.  Thus
    4.5 has the free error, but not earlier versions.

    Mostly update comments, plus make the free conditional.

    This fix was already applied to the 2.5 branch.
  ........
    r55752 | brett.cannon | 2007-06-03 16:13:41 -0700 (Sun, 03 Jun 2007) | 6 lines

    Make _strptime.TimeRE().pattern() use ``\s+`` for matching whitespace instead
    of ``\s*``.  This prevents patterns from "stealing" bits from other patterns in
    order to make a match work.

    Closes bug #1730389.  Will be backported.
  ........
    r55766 | hyeshik.chang | 2007-06-05 11:16:52 -0700 (Tue, 05 Jun 2007) | 4 lines

    Fix build on FreeBSD.  Bluetooth HCI API in FreeBSD is quite different
    from Linux's.  Just fix the build for now but the code doesn't
    support the complete capability of HCI on FreeBSD yet.
  ........
    r55770 | hyeshik.chang | 2007-06-05 11:58:51 -0700 (Tue, 05 Jun 2007) | 4 lines

    Bug #1728403: Fix a bug that CJKCodecs StreamReader hangs when it
    reads a file that ends with incomplete sequence and sizehint argument
    for .read() is specified.
  ........
    r55775 | hyeshik.chang | 2007-06-05 12:28:15 -0700 (Tue, 05 Jun 2007) | 2 lines

    Fix for Windows: close a temporary file before trying to delete it.
  ........
    r55783 | guido.van.rossum | 2007-06-05 14:24:47 -0700 (Tue, 05 Jun 2007) | 2 lines

    Patch by Tim Delany (missing DECREF). SF #1731330.
  ........
    r55785 | collin.winter | 2007-06-05 17:17:35 -0700 (Tue, 05 Jun 2007) | 3 lines

    Patch #1731049: make threading.py use a proper "raise" when checking internal state, rather than assert statements (which get stripped out by -O).
  ........
    r55786 | facundo.batista | 2007-06-06 08:13:37 -0700 (Wed, 06 Jun 2007) | 4 lines


    FTP.ntransfercmd method now uses create_connection when passive,
    using the timeout received in connection time.
  ........
    r55792 | facundo.batista | 2007-06-06 10:15:23 -0700 (Wed, 06 Jun 2007) | 7 lines


    Added an optional timeout parameter to function urllib2.urlopen,
    with tests in test_urllib2net.py (must have network resource
    enabled to execute them). Also modified test_urllib2.py because
    testing mock classes must take it into acount. Docs are also
    updated.
  ........
    r55793 | thomas.heller | 2007-06-06 13:19:19 -0700 (Wed, 06 Jun 2007) | 1 line

    Build _ctypes and _ctypes_test in the ReleaseAMD64 configuration.
  ........
    r55802 | georg.brandl | 2007-06-07 06:23:24 -0700 (Thu, 07 Jun 2007) | 3 lines

    Disallow function calls like foo(None=1).
    Backport from py3k rev. 55708 by Guido.
  ........
    r55804 | georg.brandl | 2007-06-07 06:30:24 -0700 (Thu, 07 Jun 2007) | 2 lines

    Make reindent.py executable.
  ........
    r55805 | georg.brandl | 2007-06-07 06:34:10 -0700 (Thu, 07 Jun 2007) | 2 lines

    Patch #1667860: Fix UnboundLocalError in urllib2.
  ........
    r55821 | kristjan.jonsson | 2007-06-07 16:53:49 -0700 (Thu, 07 Jun 2007) | 1 line

    Fixing changes to getbuildinfo.c that broke linux builds
  ........
    r55828 | thomas.heller | 2007-06-08 09:10:27 -0700 (Fri, 08 Jun 2007) | 1 line

    Make this test work with older Python releases where struct has no 't' format character.
  ........
    r55829 | martin.v.loewis | 2007-06-08 10:29:20 -0700 (Fri, 08 Jun 2007) | 3 lines

    Bug #1733488: Fix compilation of bufferobject.c on AIX.
    Will backport to 2.5.
  ........
    r55831 | thomas.heller | 2007-06-08 11:20:09 -0700 (Fri, 08 Jun 2007) | 2 lines

    [ 1715718 ] x64 clean compile patch for _ctypes, by Kristj?n Valur
    with small modifications.
  ........
    r55832 | thomas.heller | 2007-06-08 12:01:06 -0700 (Fri, 08 Jun 2007) | 1 line

    Fix gcc warnings intruduced by passing Py_ssize_t to PyErr_Format calls.
  ........
    r55833 | thomas.heller | 2007-06-08 12:08:31 -0700 (Fri, 08 Jun 2007) | 2 lines

    Fix wrong documentation, and correct the punktuation.
    Closes [1700455].
  ........
    r55834 | thomas.heller | 2007-06-08 12:14:23 -0700 (Fri, 08 Jun 2007) | 1 line

    Fix warnings by using proper function prototype.
  ........
    r55839 | neal.norwitz | 2007-06-08 20:36:34 -0700 (Fri, 08 Jun 2007) | 7 lines

    Prevent expandtabs() on string and unicode objects from causing a segfault when
    a large width is passed on 32-bit platforms.  Found by Google.

    It would be good for people to review this especially carefully and verify
    I don't have an off by one error and there is no other way to cause overflow.
  ........
    r55841 | neal.norwitz | 2007-06-08 21:48:22 -0700 (Fri, 08 Jun 2007) | 1 line

    Use macro version of GET_SIZE to avoid Coverity warning (#150) about a possible error.
  ........
    r55842 | martin.v.loewis | 2007-06-09 00:42:52 -0700 (Sat, 09 Jun 2007) | 3 lines

    Patch #1733960: Allow T_LONGLONG to accept ints.
    Will backport to 2.5.
  ........
    r55843 | martin.v.loewis | 2007-06-09 00:58:05 -0700 (Sat, 09 Jun 2007) | 2 lines

    Fix Windows build.
  ........
    r55845 | martin.v.loewis | 2007-06-09 03:10:26 -0700 (Sat, 09 Jun 2007) | 2 lines

    Provide LLONG_MAX for S390.
  ........
    r55854 | thomas.heller | 2007-06-10 08:59:17 -0700 (Sun, 10 Jun 2007) | 4 lines


    First version of build scripts for Windows/AMD64 (no external
    components are built yet, and 'kill_python' is disabled).
  ........
    r55855 | thomas.heller | 2007-06-10 10:55:51 -0700 (Sun, 10 Jun 2007) | 3 lines

    For now, disable the _bsddb, _sqlite3, _ssl, _testcapi, _tkinter
    modules in the ReleaseAMD64 configuration because they do not compile.
  ........
    r55856 | thomas.heller | 2007-06-10 11:27:54 -0700 (Sun, 10 Jun 2007) | 1 line

    Need to set the environment variables, otherwise devenv.com is not found.
  ........
    r55860 | thomas.heller | 2007-06-10 14:01:17 -0700 (Sun, 10 Jun 2007) | 1 line

    Revert commit 55855.
  ........
................
  r55880 | neal.norwitz | 2007-06-10 22:07:36 -0700 (Sun, 10 Jun 2007) | 5 lines

  Fix the refleak counter on test_collections.  The ABC metaclass creates
  a registry which must be cleared on each run.  Otherwise, there *seem*
  to be refleaks when there really aren't any.  (The class is held within
  the registry even though it's no longer needed.)
................
  r55884 | neal.norwitz | 2007-06-10 22:46:33 -0700 (Sun, 10 Jun 2007) | 1 line

  These tests have been removed, so they are no longer needed here
................
  r55886 | georg.brandl | 2007-06-11 00:26:37 -0700 (Mon, 11 Jun 2007) | 3 lines

  Optimize access to True and False in the compiler (if True)
  and the peepholer (LOAD_NAME True).
................
  r55905 | georg.brandl | 2007-06-11 10:02:26 -0700 (Mon, 11 Jun 2007) | 5 lines

  Remove __oct__ and __hex__ and use __index__ for converting
  non-ints before formatting in a base.

  Add a bin() builtin.
................
  r55906 | georg.brandl | 2007-06-11 10:04:44 -0700 (Mon, 11 Jun 2007) | 2 lines

  int(x, 0) does not "guess".
................
  r55907 | georg.brandl | 2007-06-11 10:05:47 -0700 (Mon, 11 Jun 2007) | 2 lines

  Add a comment to explain that nb_oct and nb_hex are nonfunctional.
................
  r55908 | guido.van.rossum | 2007-06-11 10:49:18 -0700 (Mon, 11 Jun 2007) | 2 lines

  Get rid of unused imports and comment.
................
  r55910 | guido.van.rossum | 2007-06-11 13:05:17 -0700 (Mon, 11 Jun 2007) | 2 lines

  _Abstract.__new__ now requires either no arguments or __init__ overridden.
................
  r55911 | guido.van.rossum | 2007-06-11 13:07:49 -0700 (Mon, 11 Jun 2007) | 7 lines

  Move the collections ABCs to a separate file, _abcoll.py, in order to avoid
  needing to import _collections.so during the bootstrap (this will become
  apparent in the next submit of os.py).

  Add (plain and mutable) ABCs for Set, Mapping, Sequence.
................
  r55912 | guido.van.rossum | 2007-06-11 13:09:31 -0700 (Mon, 11 Jun 2007) | 2 lines

  Rewrite the _Environ class to use the new collections ABCs.
................
  r55913 | guido.van.rossum | 2007-06-11 13:59:45 -0700 (Mon, 11 Jun 2007) | 72 lines

  Merged revisions 55869-55912 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r55869 | neal.norwitz | 2007-06-10 17:42:11 -0700 (Sun, 10 Jun 2007) | 1 line

    Add Atul Varma for patch # 1667860
  ........
    r55870 | neal.norwitz | 2007-06-10 18:22:03 -0700 (Sun, 10 Jun 2007) | 1 line

    Ignore valgrind problems on Ubuntu from ld
  ........
    r55872 | neal.norwitz | 2007-06-10 18:48:46 -0700 (Sun, 10 Jun 2007) | 2 lines

    Ignore config.status.lineno which seems new (new autoconf?)
  ........
    r55873 | neal.norwitz | 2007-06-10 19:14:39 -0700 (Sun, 10 Jun 2007) | 1 line

    Prevent these tests from running on Win64 since they don\'t apply there either
  ........
    r55874 | neal.norwitz | 2007-06-10 19:16:10 -0700 (Sun, 10 Jun 2007) | 5 lines

    Fix a bug when there was a newline in the string expandtabs was called on.
    This also catches another condition that can overflow.

    Will backport.
  ........
    r55879 | neal.norwitz | 2007-06-10 21:52:37 -0700 (Sun, 10 Jun 2007) | 1 line

    Prevent hang if the port cannot be opened.
  ........
    r55881 | neal.norwitz | 2007-06-10 22:28:45 -0700 (Sun, 10 Jun 2007) | 4 lines

    Add all of the distuils modules that don't seem to have explicit tests. :-(
    Move an import in mworkscompiler so that this module can be imported on
    any platform.  Hopefully this works on all platforms.
  ........
    r55882 | neal.norwitz | 2007-06-10 22:35:10 -0700 (Sun, 10 Jun 2007) | 4 lines

    SF #1734732, lower case the module names per PEP 8.

    Will backport.
  ........
    r55885 | neal.norwitz | 2007-06-10 23:16:48 -0700 (Sun, 10 Jun 2007) | 4 lines

    Not sure why this only fails sometimes on Unix machines. Better
    to disable it and only import msvccompiler on Windows since that's
    the only place it can work anyways.
  ........
    r55887 | neal.norwitz | 2007-06-11 00:29:43 -0700 (Mon, 11 Jun 2007) | 4 lines

    Bug #1734723: Fix repr.Repr() so it doesn't ignore the maxtuple attribute.

    Will backport
  ........
    r55889 | neal.norwitz | 2007-06-11 00:36:24 -0700 (Mon, 11 Jun 2007) | 1 line

    Reflow long line
  ........
    r55896 | thomas.heller | 2007-06-11 08:58:33 -0700 (Mon, 11 Jun 2007) | 3 lines

    Use "O&" in calls to PyArg_Parse when we need a 'void*' instead of "k"
    or "K" codes.
  ........
    r55901 | facundo.batista | 2007-06-11 09:27:08 -0700 (Mon, 11 Jun 2007) | 5 lines


    Added versionchanged flag to all the methods which received
    a new optional timeout parameter, and a versionadded flag to
    the socket.create_connection function.
  ........
................
  r55914 | guido.van.rossum | 2007-06-11 14:19:50 -0700 (Mon, 11 Jun 2007) | 3 lines

  New super() implementation, for PEP 3135 (though the PEP is not yet updated
  to this design, and small tweaks may still be made later).
................
  r55923 | guido.van.rossum | 2007-06-11 21:15:24 -0700 (Mon, 11 Jun 2007) | 4 lines

  I'm guessing this module broke when Neal ripped out the types module --
  it used 'list' both as a local variable and as the built-in list type.
  Renamed the local variable since that was easier.
................
  r55924 | guido.van.rossum | 2007-06-11 21:20:05 -0700 (Mon, 11 Jun 2007) | 5 lines

  Change all occurrences of super(<thisclass>, <firstarg>) to super().
  Seems to have worked, all the tests still pass.
  Exception: test_descr and test_descrtut, which have tons of these
  and are there to test the various usages.
................
  r55939 | collin.winter | 2007-06-12 13:57:33 -0700 (Tue, 12 Jun 2007) | 1 line

  Patch #1735485: remove StandardError from the exception hierarchy.
................
  r55954 | neal.norwitz | 2007-06-12 21:56:32 -0700 (Tue, 12 Jun 2007) | 51 lines

  Merged revisions 55913-55950 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r55926 | marc-andre.lemburg | 2007-06-12 02:09:58 -0700 (Tue, 12 Jun 2007) | 3 lines

    Apply patch #1734945 to support TurboLinux as distribution.
  ........
    r55927 | marc-andre.lemburg | 2007-06-12 02:26:49 -0700 (Tue, 12 Jun 2007) | 3 lines

    Add patch #1726668: Windows Vista support.
  ........
    r55929 | thomas.heller | 2007-06-12 08:36:22 -0700 (Tue, 12 Jun 2007) | 1 line

    Checkout, but do not yet try to build, exernal sources.
  ........
    r55930 | thomas.heller | 2007-06-12 09:08:27 -0700 (Tue, 12 Jun 2007) | 6 lines

    Add bufferoverflowU.lib to the libraries needed by _ssl (is this the
    right thing to do?).

    Set the /XP64 /RETAIL build enviroment in the makefile when building
    ReleaseAMD64.
  ........
    r55931 | thomas.heller | 2007-06-12 09:23:19 -0700 (Tue, 12 Jun 2007) | 5 lines

    Revert this change, since it breaks the win32 build:

    Add bufferoverflowU.lib to the libraries needed by _ssl (is this the
    right thing to do?).
  ........
    r55934 | thomas.heller | 2007-06-12 10:28:31 -0700 (Tue, 12 Jun 2007) | 3 lines

    Specify the bufferoverflowU.lib to the makefile on the command line
    (for ReleaseAMD64 builds).
  ........
    r55937 | thomas.heller | 2007-06-12 12:02:59 -0700 (Tue, 12 Jun 2007) | 3 lines

    Add bufferoverflowU.lib to PCBuild\_bsddb.vcproj.
    Build sqlite3.dll and bsddb.
  ........
    r55938 | thomas.heller | 2007-06-12 12:56:12 -0700 (Tue, 12 Jun 2007) | 2 lines

    Don't rebuild Berkeley DB if not needed (this was committed by accident).
  ........
    r55948 | martin.v.loewis | 2007-06-12 20:42:19 -0700 (Tue, 12 Jun 2007) | 3 lines

    Provide PY_LLONG_MAX on all systems having long long.
    Will backport to 2.5.
  ........
................
  r55959 | guido.van.rossum | 2007-06-13 09:22:41 -0700 (Wed, 13 Jun 2007) | 2 lines

  Fix a compilation warning.
................
2007-06-13 18:07:49 +00:00

427 lines
16 KiB
TeX

\section{Built-in Exceptions}
\declaremodule{standard}{exceptions}
\modulesynopsis{Standard exception classes.}
Exceptions should be class objects.
The exceptions are defined in the module \module{exceptions}. This
module never needs to be imported explicitly: the exceptions are
provided in the built-in namespace as well as the \module{exceptions}
module.
For class exceptions, in a \keyword{try}\stindex{try} statement with
an \keyword{except}\stindex{except} clause that mentions a particular
class, that clause also handles any exception classes derived from
that class (but not exception classes from which \emph{it} is
derived). Two exception classes that are not related via subclassing
are never equivalent, even if they have the same name.
The built-in exceptions listed below can be generated by the
interpreter or built-in functions. Except where mentioned, they have
an ``associated value'' indicating the detailed cause of the error.
This may be a string or a tuple containing several items of
information (e.g., an error code and a string explaining the code).
The associated value is the second argument to the
\keyword{raise}\stindex{raise} statement. If the exception class is
derived from the standard root class \exception{BaseException}, the
associated value is present as the exception instance's \member{args}
attribute.
User code can raise built-in exceptions. This can be used to test an
exception handler or to report an error condition ``just like'' the
situation in which the interpreter raises the same exception; but
beware that there is nothing to prevent user code from raising an
inappropriate error.
The built-in exception classes can be sub-classed to define new
exceptions; programmers are encouraged to at least derive new
exceptions from the \exception{Exception} class and not
\exception{BaseException}. More
information on defining exceptions is available in the
\citetitle[../tut/tut.html]{Python Tutorial} under the heading
``User-defined Exceptions.''
\setindexsubitem{(built-in exception base class)}
The following exceptions are only used as base classes for other
exceptions.
\begin{excdesc}{BaseException}
The base class for all built-in exceptions. It is not meant to be directly
inherited by user-defined classes (for that use \exception{Exception}). If
\function{str()} or \function{unicode()} is called on an instance of this
class, the representation of the argument(s) to the instance are returned or
the emptry string when there were no arguments. All arguments are
stored in \member{args} as a tuple.
\versionadded{2.5}
\end{excdesc}
\begin{excdesc}{Exception}
All built-in, non-system-exiting exceptions are derived
from this class. All user-defined exceptions should also be derived
from this class.
\versionchanged[Changed to inherit from \exception{BaseException}]{2.5}
\end{excdesc}
\begin{excdesc}{ArithmeticError}
The base class for those built-in exceptions that are raised for
various arithmetic errors: \exception{OverflowError},
\exception{ZeroDivisionError}, \exception{FloatingPointError}.
\end{excdesc}
\begin{excdesc}{LookupError}
The base class for the exceptions that are raised when a key or
index used on a mapping or sequence is invalid: \exception{IndexError},
\exception{KeyError}. This can be raised directly by
\function{sys.setdefaultencoding()}.
\end{excdesc}
\begin{excdesc}{EnvironmentError}
The base class for exceptions that
can occur outside the Python system: \exception{IOError},
\exception{OSError}. When exceptions of this type are created with a
2-tuple, the first item is available on the instance's \member{errno}
attribute (it is assumed to be an error number), and the second item
is available on the \member{strerror} attribute (it is usually the
associated error message). The tuple itself is also available on the
\member{args} attribute.
\versionadded{1.5.2}
When an \exception{EnvironmentError} exception is instantiated with a
3-tuple, the first two items are available as above, while the third
item is available on the \member{filename} attribute. However, for
backwards compatibility, the \member{args} attribute contains only a
2-tuple of the first two constructor arguments.
The \member{filename} attribute is \code{None} when this exception is
created with other than 3 arguments. The \member{errno} and
\member{strerror} attributes are also \code{None} when the instance was
created with other than 2 or 3 arguments. In this last case,
\member{args} contains the verbatim constructor arguments as a tuple.
\end{excdesc}
\setindexsubitem{(built-in exception)}
The following exceptions are the exceptions that are actually raised.
\begin{excdesc}{AssertionError}
\stindex{assert}
Raised when an \keyword{assert} statement fails.
\end{excdesc}
\begin{excdesc}{AttributeError}
% xref to attribute reference?
Raised when an attribute reference or assignment fails. (When an
object does not support attribute references or attribute assignments
at all, \exception{TypeError} is raised.)
\end{excdesc}
\begin{excdesc}{EOFError}
% XXXJH xrefs here
Raised when attempting to read beyond the end of a file.
% XXXJH xrefs here
(N.B.: the \method{read()} and \method{readline()} methods of file
objects return an empty string when they hit \EOF.)
\end{excdesc}
\begin{excdesc}{FloatingPointError}
Raised when a floating point operation fails. This exception is
always defined, but can only be raised when Python is configured
with the \longprogramopt{with-fpectl} option, or the
\constant{WANT_SIGFPE_HANDLER} symbol is defined in the
\file{pyconfig.h} file.
\end{excdesc}
\begin{excdesc}{GeneratorExit}
Raise when a generator's \method{close()} method is called.
\versionadded{2.5}
\versionchanged[Changed to inherit from Exception instead of
StandardError]{3.0}
\end{excdesc}
\begin{excdesc}{IOError}
% XXXJH xrefs here
Raised when an I/O operation (such as a \keyword{print} statement,
the built-in \function{open()} function or a method of a file
object) fails for an I/O-related reason, e.g., ``file not found'' or
``disk full''.
This class is derived from \exception{EnvironmentError}. See the
discussion above for more information on exception instance
attributes.
\end{excdesc}
\begin{excdesc}{ImportError}
% XXXJH xref to import statement?
Raised when an \keyword{import} statement fails to find the module
definition or when a \code{from \textrm{\ldots} import} fails to find a
name that is to be imported.
\end{excdesc}
\begin{excdesc}{IndexError}
% XXXJH xref to sequences
Raised when a sequence subscript is out of range. (Slice indices are
silently truncated to fall in the allowed range; if an index is not a
plain integer, \exception{TypeError} is raised.)
\end{excdesc}
\begin{excdesc}{KeyError}
% XXXJH xref to mapping objects?
Raised when a mapping (dictionary) key is not found in the set of
existing keys.
\end{excdesc}
\begin{excdesc}{KeyboardInterrupt}
Raised when the user hits the interrupt key (normally
\kbd{Control-C} or \kbd{Delete}). During execution, a check for
interrupts is made regularly.
% XXX(hylton) xrefs here
The exception inherits from \exception{BaseException} so as to not be
accidentally caught by code that catches \exception{Exception} and thus
prevent the interpreter from exiting.
\versionchanged[Changed to inherit from \exception{BaseException}]{2.5}
\end{excdesc}
\begin{excdesc}{MemoryError}
Raised when an operation runs out of memory but the situation may
still be rescued (by deleting some objects). The associated value is
a string indicating what kind of (internal) operation ran out of memory.
Note that because of the underlying memory management architecture
(C's \cfunction{malloc()} function), the interpreter may not
always be able to completely recover from this situation; it
nevertheless raises an exception so that a stack traceback can be
printed, in case a run-away program was the cause.
\end{excdesc}
\begin{excdesc}{NameError}
Raised when a local or global name is not found. This applies only
to unqualified names. The associated value is an error message that
includes the name that could not be found.
\end{excdesc}
\begin{excdesc}{NotImplementedError}
This exception is derived from \exception{RuntimeError}. In user
defined base classes, abstract methods should raise this exception
when they require derived classes to override the method.
\versionadded{1.5.2}
\end{excdesc}
\begin{excdesc}{OSError}
%xref for os module
This class is derived from \exception{EnvironmentError} and is used
primarily as the \refmodule{os} module's \code{os.error} exception.
See \exception{EnvironmentError} above for a description of the
possible associated values.
\versionadded{1.5.2}
\end{excdesc}
\begin{excdesc}{OverflowError}
% XXXJH reference to long's and/or int's?
Raised when the result of an arithmetic operation is too large to be
represented. This cannot occur for long integers (which would rather
raise \exception{MemoryError} than give up). Because of the lack of
standardization of floating point exception handling in C, most
floating point operations also aren't checked. For plain integers,
all operations that can overflow are checked except left shift, where
typical applications prefer to drop bits than raise an exception.
\end{excdesc}
\begin{excdesc}{ReferenceError}
This exception is raised when a weak reference proxy, created by the
\function{\refmodule{weakref}.proxy()} function, is used to access
an attribute of the referent after it has been garbage collected.
For more information on weak references, see the \refmodule{weakref}
module.
\versionadded[Previously known as the
\exception{\refmodule{weakref}.ReferenceError}
exception]{2.2}
\end{excdesc}
\begin{excdesc}{RuntimeError}
Raised when an error is detected that doesn't fall in any of the
other categories. The associated value is a string indicating what
precisely went wrong. (This exception is mostly a relic from a
previous version of the interpreter; it is not used very much any
more.)
\end{excdesc}
\begin{excdesc}{StopIteration}
Raised by builtin \function{next()} and an iterator's \method{__next__()}
method to signal that there are no further values.
\versionadded{2.2}
\versionchanged[Changed to inherit from Exception instead of
StandardError]{3.0}
\end{excdesc}
\begin{excdesc}{SyntaxError}
% XXXJH xref to these functions?
Raised when the parser encounters a syntax error. This may occur in
an \keyword{import} statement, in a call to the built-in functions
\function{exec()}, \function{execfile()}, \function{eval()} or
\function{input()}, or when reading the initial script or standard
input (also interactively).
Instances of this class have attributes \member{filename},
\member{lineno}, \member{offset} and \member{text} for easier access
to the details. \function{str()} of the exception instance returns
only the message.
\end{excdesc}
\begin{excdesc}{SystemError}
Raised when the interpreter finds an internal error, but the
situation does not look so serious to cause it to abandon all hope.
The associated value is a string indicating what went wrong (in
low-level terms).
You should report this to the author or maintainer of your Python
interpreter. Be sure to report the version of the Python
interpreter (\code{sys.version}; it is also printed at the start of an
interactive Python session), the exact error message (the exception's
associated value) and if possible the source of the program that
triggered the error.
\end{excdesc}
\begin{excdesc}{SystemExit}
% XXX(hylton) xref to module sys?
This exception is raised by the \function{sys.exit()} function. When it
is not handled, the Python interpreter exits; no stack traceback is
printed. If the associated value is a plain integer, it specifies the
system exit status (passed to C's \cfunction{exit()} function); if it is
\code{None}, the exit status is zero; if it has another type (such as
a string), the object's value is printed and the exit status is one.
Instances have an attribute \member{code} which is set to the
proposed exit status or error message (defaulting to \code{None}).
Also, this exception derives directly from \exception{BaseException} and
not \exception{Exception}, since it is not technically an error.
A call to \function{sys.exit()} is translated into an exception so that
clean-up handlers (\keyword{finally} clauses of \keyword{try} statements)
can be executed, and so that a debugger can execute a script without
running the risk of losing control. The \function{os._exit()} function
can be used if it is absolutely positively necessary to exit
immediately (for example, in the child process after a call to
\function{fork()}).
The exception inherits from \exception{BaseException} instead of
\exception{Exception} so that it is not
accidentally caught by code that catches \exception{Exception}. This allows
the exception to properly propagate up and cause the interpreter to exit.
\versionchanged[Changed to inherit from \exception{BaseException}]{2.5}
\end{excdesc}
\begin{excdesc}{TypeError}
Raised when an operation or function is applied to an object
of inappropriate type. The associated value is a string giving
details about the type mismatch.
\end{excdesc}
\begin{excdesc}{UnboundLocalError}
Raised when a reference is made to a local variable in a function or
method, but no value has been bound to that variable. This is a
subclass of \exception{NameError}.
\versionadded{2.0}
\end{excdesc}
\begin{excdesc}{UnicodeError}
Raised when a Unicode-related encoding or decoding error occurs. It
is a subclass of \exception{ValueError}.
\versionadded{2.0}
\end{excdesc}
\begin{excdesc}{UnicodeEncodeError}
Raised when a Unicode-related error occurs during encoding. It
is a subclass of \exception{UnicodeError}.
\versionadded{2.3}
\end{excdesc}
\begin{excdesc}{UnicodeDecodeError}
Raised when a Unicode-related error occurs during decoding. It
is a subclass of \exception{UnicodeError}.
\versionadded{2.3}
\end{excdesc}
\begin{excdesc}{UnicodeTranslateError}
Raised when a Unicode-related error occurs during translating. It
is a subclass of \exception{UnicodeError}.
\versionadded{2.3}
\end{excdesc}
\begin{excdesc}{ValueError}
Raised when a built-in operation or function receives an argument
that has the right type but an inappropriate value, and the
situation is not described by a more precise exception such as
\exception{IndexError}.
\end{excdesc}
\begin{excdesc}{WindowsError}
Raised when a Windows-specific error occurs or when the error number
does not correspond to an \cdata{errno} value. The
\member{winerror} and \member{strerror} values are created from the
return values of the \cfunction{GetLastError()} and
\cfunction{FormatMessage()} functions from the Windows Platform API.
The \member{errno} value maps the \member{winerror} value to
corresponding \code{errno.h} values.
This is a subclass of \exception{OSError}.
\versionadded{2.0}
\versionchanged[Previous versions put the \cfunction{GetLastError()}
codes into \member{errno}]{2.5}
\end{excdesc}
\begin{excdesc}{ZeroDivisionError}
Raised when the second argument of a division or modulo operation is
zero. The associated value is a string indicating the type of the
operands and the operation.
\end{excdesc}
\setindexsubitem{(built-in warning)}
The following exceptions are used as warning categories; see the
\refmodule{warnings} module for more information.
\begin{excdesc}{Warning}
Base class for warning categories.
\end{excdesc}
\begin{excdesc}{UserWarning}
Base class for warnings generated by user code.
\end{excdesc}
\begin{excdesc}{DeprecationWarning}
Base class for warnings about deprecated features.
\end{excdesc}
\begin{excdesc}{PendingDeprecationWarning}
Base class for warnings about features which will be deprecated in the future.
\end{excdesc}
\begin{excdesc}{SyntaxWarning}
Base class for warnings about dubious syntax
\end{excdesc}
\begin{excdesc}{RuntimeWarning}
Base class for warnings about dubious runtime behavior.
\end{excdesc}
\begin{excdesc}{FutureWarning}
Base class for warnings about constructs that will change semantically
in the future.
\end{excdesc}
\begin{excdesc}{ImportWarning}
Base class for warnings about probable mistakes in module imports.
\versionadded{2.5}
\end{excdesc}
\begin{excdesc}{UnicodeWarning}
Base class for warnings related to Unicode.
\versionadded{2.5}
\end{excdesc}
The class hierarchy for built-in exceptions is:
\verbatiminput{../../Lib/test/exception_hierarchy.txt}