Name	Size	Mode	Actions
2to3.rst.txt	14647	0644	editdlrm
abc.rst.txt	7219	0644	editdlrm
aepack.rst.txt	4257	0644	editdlrm
aetools.rst.txt	3532	0644	editdlrm
aetypes.rst.txt	4257	0644	editdlrm
aifc.rst.txt	7086	0644	editdlrm
al.rst.txt	5309	0644	editdlrm
allos.rst.txt	695	0644	editdlrm
anydbm.rst.txt	4111	0644	editdlrm
archiving.rst.txt	424	0644	editdlrm
argparse.rst.txt	74685	0644	editdlrm
array.rst.txt	10524	0644	editdlrm
ast.rst.txt	10111	0644	editdlrm
asynchat.rst.txt	9206	0644	editdlrm
asyncore.rst.txt	12937	0644	editdlrm
atexit.rst.txt	3910	0644	editdlrm
audioop.rst.txt	10395	0644	editdlrm
autogil.rst.txt	1015	0644	editdlrm
base64.rst.txt	6252	0644	editdlrm
basehttpserver.rst.txt	10404	0644	editdlrm
bastion.rst.txt	2611	0644	editdlrm
bdb.rst.txt	12456	0644	editdlrm
binascii.rst.txt	6508	0644	editdlrm
binhex.rst.txt	1910	0644	editdlrm
bisect.rst.txt	5415	0644	editdlrm
bsddb.rst.txt	7575	0644	editdlrm
bz2.rst.txt	8064	0644	editdlrm
calendar.rst.txt	11282	0644	editdlrm
carbon.rst.txt	15956	0644	editdlrm
cd.rst.txt	11974	0644	editdlrm
cgi.rst.txt	22853	0644	editdlrm
cgihttpserver.rst.txt	2788	0644	editdlrm
cgitb.rst.txt	2874	0644	editdlrm
chunk.rst.txt	4955	0644	editdlrm
cmath.rst.txt	7647	0644	editdlrm
cmd.rst.txt	8565	0644	editdlrm
code.rst.txt	7115	0644	editdlrm
codecs.rst.txt	66966	0644	editdlrm
codeop.rst.txt	3774	0644	editdlrm
collections.rst.txt	41448	0644	editdlrm
colorpicker.rst.txt	913	0644	editdlrm
colorsys.rst.txt	1819	0644	editdlrm
commands.rst.txt	2595	0644	editdlrm
compileall.rst.txt	4678	0644	editdlrm
compiler.rst.txt	37464	0644	editdlrm
configparser.rst.txt	19607	0644	editdlrm
constants.rst.txt	2328	0644	editdlrm
contextlib.rst.txt	6012	0644	editdlrm
cookie.rst.txt	9543	0644	editdlrm
cookielib.rst.txt	27875	0644	editdlrm
copy.rst.txt	3351	0644	editdlrm
copy_reg.rst.txt	2329	0644	editdlrm
crypt.rst.txt	2292	0644	editdlrm
crypto.rst.txt	355	0644	editdlrm
csv.rst.txt	22757	0644	editdlrm
ctypes.rst.txt	90513	0644	editdlrm
curses.ascii.rst.txt	9046	0644	editdlrm
curses.panel.rst.txt	2740	0644	editdlrm
curses.rst.txt	74877	0644	editdlrm
custominterp.rst.txt	570	0644	editdlrm
datatypes.rst.txt	864	0644	editdlrm
datetime.rst.txt	74679	0644	editdlrm
dbhash.rst.txt	3865	0644	editdlrm
dbm.rst.txt	3117	0644	editdlrm
debug.rst.txt	446	0644	editdlrm
decimal.rst.txt	70926	0644	editdlrm
development.rst.txt	640	0644	editdlrm
difflib.rst.txt	30716	0644	editdlrm
dircache.rst.txt	1813	0644	editdlrm
dis.rst.txt	23248	0644	editdlrm
distribution.rst.txt	426	0644	editdlrm
distutils.rst.txt	1958	0644	editdlrm
dl.rst.txt	3392	0644	editdlrm
doctest.rst.txt	73985	0644	editdlrm
docxmlrpcserver.rst.txt	3802	0644	editdlrm
dumbdbm.rst.txt	2841	0644	editdlrm
dummy_thread.rst.txt	1058	0644	editdlrm
dummy_threading.rst.txt	799	0644	editdlrm
easydialogs.rst.txt	10346	0644	editdlrm
email-examples.rst.txt	1271	0644	editdlrm
email.charset.rst.txt	9654	0644	editdlrm
email.encoders.rst.txt	2376	0644	editdlrm
email.errors.rst.txt	4006	0644	editdlrm
email.generator.rst.txt	6132	0644	editdlrm
email.header.rst.txt	7531	0644	editdlrm
email.iterators.rst.txt	2421	0644	editdlrm
email.message.rst.txt	25217	0644	editdlrm
email.mime.rst.txt	9917	0644	editdlrm
email.parser.rst.txt	10327	0644	editdlrm
email.rst.txt	16111	0644	editdlrm
email.utils.rst.txt	6475	0644	editdlrm
ensurepip.rst.txt	5022	0644	editdlrm
errno.rst.txt	6708	0644	editdlrm
exceptions.rst.txt	18343	0644	editdlrm
fcntl.rst.txt	7361	0644	editdlrm
filecmp.rst.txt	5348	0644	editdlrm
fileformats.rst.txt	302	0644	editdlrm
fileinput.rst.txt	7417	0644	editdlrm
filesys.rst.txt	806	0644	editdlrm
fl.rst.txt	17646	0644	editdlrm
fm.rst.txt	2699	0644	editdlrm
fnmatch.rst.txt	3104	0644	editdlrm
formatter.rst.txt	13245	0644	editdlrm
fpectl.rst.txt	4171	0644	editdlrm
fpformat.rst.txt	1747	0644	editdlrm
fractions.rst.txt	5297	0644	editdlrm
framework.rst.txt	11444	0644	editdlrm
frameworks.rst.txt	378	0644	editdlrm
ftplib.rst.txt	15720	0644	editdlrm
functions.rst.txt	75554	0644	editdlrm
functools.rst.txt	7448	0644	editdlrm
future_builtins.rst.txt	2010	0644	editdlrm
gc.rst.txt	9014	0644	editdlrm
gdbm.rst.txt	4882	0644	editdlrm
gensuitemodule.rst.txt	3113	0644	editdlrm
getopt.rst.txt	6670	0644	editdlrm
getpass.rst.txt	1876	0644	editdlrm
gettext.rst.txt	29040	0644	editdlrm
gl.rst.txt	6009	0644	editdlrm
glob.rst.txt	2414	0644	editdlrm
grp.rst.txt	2256	0644	editdlrm
gzip.rst.txt	4828	0644	editdlrm
hashlib.rst.txt	7379	0644	editdlrm
heapq.rst.txt	13185	0644	editdlrm
hmac.rst.txt	3073	0644	editdlrm
hotshot.rst.txt	4289	0644	editdlrm
htmllib.rst.txt	7379	0644	editdlrm
htmlparser.rst.txt	11640	0644	editdlrm
httplib.rst.txt	37454	0644	editdlrm
i18n.rst.txt	409	0644	editdlrm
ic.rst.txt	5005	0644	editdlrm
idle.rst.txt	22182	0644	editdlrm
imageop.rst.txt	4001	0644	editdlrm
imaplib.rst.txt	17221	0644	editdlrm
imgfile.rst.txt	2765	0644	editdlrm
imghdr.rst.txt	2635	0644	editdlrm
imp.rst.txt	12593	0644	editdlrm
importlib.rst.txt	1126	0644	editdlrm
imputil.rst.txt	7023	0644	editdlrm
index.rst.txt	2287	0644	editdlrm
inspect.rst.txt	28151	0644	editdlrm
internet.rst.txt	950	0644	editdlrm
intro.rst.txt	2803	0644	editdlrm
io.rst.txt	39015	0644	editdlrm
ipc.rst.txt	630	0644	editdlrm
itertools.rst.txt	36324	0644	editdlrm
jpeg.rst.txt	3858	0644	editdlrm
json.rst.txt	25545	0644	editdlrm
keyword.rst.txt	617	0644	editdlrm
language.rst.txt	523	0644	editdlrm
linecache.rst.txt	1887	0644	editdlrm
locale.rst.txt	24975	0644	editdlrm
logging.config.rst.txt	31560	0644	editdlrm
logging.handlers.rst.txt	28153	0644	editdlrm
logging.rst.txt	46882	0644	editdlrm
mac.rst.txt	791	0644	editdlrm
macos.rst.txt	3824	0644	editdlrm
macosa.rst.txt	3964	0644	editdlrm
macostools.rst.txt	4017	0644	editdlrm
macpath.rst.txt	650	0644	editdlrm
mailbox.rst.txt	68129	0644	editdlrm
mailcap.rst.txt	3675	0644	editdlrm
markup.rst.txt	1249	0644	editdlrm
marshal.rst.txt	5689	0644	editdlrm
math.rst.txt	10920	0644	editdlrm
md5.rst.txt	2815	0644	editdlrm
mhlib.rst.txt	3966	0644	editdlrm
mimetools.rst.txt	4504	0644	editdlrm
mimetypes.rst.txt	9839	0644	editdlrm
mimewriter.rst.txt	3360	0644	editdlrm
mimify.rst.txt	3519	0644	editdlrm
miniaeframe.rst.txt	2564	0644	editdlrm
misc.rst.txt	248	0644	editdlrm
mm.rst.txt	447	0644	editdlrm
mmap.rst.txt	10481	0644	editdlrm
modulefinder.rst.txt	3380	0644	editdlrm
modules.rst.txt	382	0644	editdlrm
msilib.rst.txt	19062	0644	editdlrm
msvcrt.rst.txt	4346	0644	editdlrm
multifile.rst.txt	6613	0644	editdlrm
multiprocessing.rst.txt	92621	0644	editdlrm
mutex.rst.txt	1939	0644	editdlrm
netdata.rst.txt	432	0644	editdlrm
netrc.rst.txt	3119	0644	editdlrm
new.rst.txt	2653	0644	editdlrm
nis.rst.txt	2108	0644	editdlrm
nntplib.rst.txt	14531	0644	editdlrm
numbers.rst.txt	8007	0644	editdlrm
numeric.rst.txt	751	0644	editdlrm
operator.rst.txt	22092	0644	editdlrm
optparse.rst.txt	77101	0644	editdlrm
os.path.rst.txt	13094	0644	editdlrm
os.rst.txt	82580	0644	editdlrm
ossaudiodev.rst.txt	17309	0644	editdlrm
othergui.rst.txt	2721	0644	editdlrm
parser.rst.txt	15385	0644	editdlrm
pdb.rst.txt	16043	0644	editdlrm
persistence.rst.txt	826	0644	editdlrm
pickle.rst.txt	37262	0644	editdlrm
pickletools.rst.txt	1997	0644	editdlrm
pipes.rst.txt	3786	0644	editdlrm
pkgutil.rst.txt	7714	0644	editdlrm
platform.rst.txt	9554	0644	editdlrm
plistlib.rst.txt	4134	0644	editdlrm
popen2.rst.txt	7022	0644	editdlrm
poplib.rst.txt	6220	0644	editdlrm
posix.rst.txt	3630	0644	editdlrm
posixfile.rst.txt	7200	0644	editdlrm
pprint.rst.txt	9071	0644	editdlrm
profile.rst.txt	28666	0644	editdlrm
pty.rst.txt	1762	0644	editdlrm
pwd.rst.txt	2725	0644	editdlrm
pyclbr.rst.txt	3296	0644	editdlrm
pydoc.rst.txt	4083	0644	editdlrm
pyexpat.rst.txt	28891	0644	editdlrm
python.rst.txt	514	0644	editdlrm
py_compile.rst.txt	2479	0644	editdlrm
queue.rst.txt	7034	0644	editdlrm
quopri.rst.txt	2670	0644	editdlrm
random.rst.txt	13319	0644	editdlrm
re.rst.txt	55102	0644	editdlrm
readline.rst.txt	10513	0644	editdlrm
repr.rst.txt	4718	0644	editdlrm
resource.rst.txt	9595	0644	editdlrm
restricted.rst.txt	3327	0644	editdlrm
rexec.rst.txt	11742	0644	editdlrm
rfc822.rst.txt	14037	0644	editdlrm
rlcompleter.rst.txt	2494	0644	editdlrm
robotparser.rst.txt	2190	0644	editdlrm
runpy.rst.txt	6938	0644	editdlrm
sched.rst.txt	4644	0644	editdlrm
scrolledtext.rst.txt	1379	0644	editdlrm
select.rst.txt	20705	0644	editdlrm
sets.rst.txt	14973	0644	editdlrm
sgi.rst.txt	322	0644	editdlrm
sgmllib.rst.txt	10664	0644	editdlrm
sha.rst.txt	2807	0644	editdlrm
shelve.rst.txt	8319	0644	editdlrm
shlex.rst.txt	11313	0644	editdlrm
shutil.rst.txt	13491	0644	editdlrm
signal.rst.txt	10719	0644	editdlrm
simplehttpserver.rst.txt	4559	0644	editdlrm
simplexmlrpcserver.rst.txt	10881	0644	editdlrm
site.rst.txt	7880	0644	editdlrm
smtpd.rst.txt	2464	0644	editdlrm
smtplib.rst.txt	14906	0644	editdlrm
sndhdr.rst.txt	1759	0644	editdlrm
socket.rst.txt	40765	0644	editdlrm
socketserver.rst.txt	22512	0644	editdlrm
someos.rst.txt	599	0644	editdlrm
spwd.rst.txt	2825	0644	editdlrm
sqlite3.rst.txt	35448	0644	editdlrm
ssl.rst.txt	76554	0644	editdlrm
stat.rst.txt	7778	0644	editdlrm
statvfs.rst.txt	1300	0644	editdlrm
stdtypes.rst.txt	122668	0644	editdlrm
string.rst.txt	44085	0644	editdlrm
stringio.rst.txt	4166	0644	editdlrm
stringprep.rst.txt	4238	0644	editdlrm
strings.rst.txt	746	0644	editdlrm
struct.rst.txt	17100	0644	editdlrm
subprocess.rst.txt	33648	0644	editdlrm
sun.rst.txt	249	0644	editdlrm
sunau.rst.txt	7124	0644	editdlrm
sunaudio.rst.txt	5849	0644	editdlrm
symbol.rst.txt	975	0644	editdlrm
symtable.rst.txt	5064	0644	editdlrm
sys.rst.txt	47520	0644	editdlrm
sysconfig.rst.txt	7639	0644	editdlrm
syslog.rst.txt	3931	0644	editdlrm
tabnanny.rst.txt	1999	0644	editdlrm
tarfile.rst.txt	28214	0644	editdlrm
telnetlib.rst.txt	7482	0644	editdlrm
tempfile.rst.txt	10504	0644	editdlrm
termios.rst.txt	3733	0644	editdlrm
test.rst.txt	17659	0644	editdlrm
textwrap.rst.txt	8552	0644	editdlrm
thread.rst.txt	6588	0644	editdlrm
threading.rst.txt	32468	0644	editdlrm
time.rst.txt	26020	0644	editdlrm
timeit.rst.txt	11598	0644	editdlrm
tix.rst.txt	22693	0644	editdlrm
tk.rst.txt	1612	0644	editdlrm
tkinter.rst.txt	33456	0644	editdlrm
token.rst.txt	2451	0644	editdlrm
tokenize.rst.txt	5570	0644	editdlrm
trace.rst.txt	6724	0644	editdlrm
traceback.rst.txt	10711	0644	editdlrm
ttk.rst.txt	57411	0644	editdlrm
tty.rst.txt	1011	0644	editdlrm
turtle.rst.txt	64097	0644	editdlrm
types.rst.txt	6200	0644	editdlrm
undoc.rst.txt	6550	0644	editdlrm
unicodedata.rst.txt	5736	0644	editdlrm
unittest.rst.txt	82952	0644	editdlrm
unix.rst.txt	490	0644	editdlrm
urllib.rst.txt	24960	0644	editdlrm
urllib2.rst.txt	35211	0644	editdlrm
urlparse.rst.txt	16071	0644	editdlrm
user.rst.txt	2748	0644	editdlrm
userdict.rst.txt	9290	0644	editdlrm
uu.rst.txt	2369	0644	editdlrm
uuid.rst.txt	8378	0644	editdlrm
warnings.rst.txt	19815	0644	editdlrm
wave.rst.txt	5047	0644	editdlrm
weakref.rst.txt	12926	0644	editdlrm
webbrowser.rst.txt	9863	0644	editdlrm
whichdb.rst.txt	931	0644	editdlrm
windows.rst.txt	273	0644	editdlrm
winsound.rst.txt	5066	0644	editdlrm
wsgiref.rst.txt	30567	0644	editdlrm
xdrlib.rst.txt	8077	0644	editdlrm
xml.dom.minidom.rst.txt	11208	0644	editdlrm
xml.dom.pulldom.rst.txt	1571	0644	editdlrm
xml.dom.rst.txt	40182	0644	editdlrm
xml.etree.elementtree.rst.txt	35707	0644	editdlrm
xml.rst.txt	6090	0644	editdlrm
xml.sax.handler.rst.txt	15371	0644	editdlrm
xml.sax.reader.rst.txt	12257	0644	editdlrm
xml.sax.rst.txt	6460	0644	editdlrm
xml.sax.utils.rst.txt	3560	0644	editdlrm
xmlrpclib.rst.txt	22559	0644	editdlrm
zipfile.rst.txt	18871	0644	editdlrm
zipimport.rst.txt	5957	0644	editdlrm
zlib.rst.txt	12766	0644	editdlrm
_winreg.rst.txt	23305	0644	editdlrm
__builtin__.rst.txt	1494	0644	editdlrm
__future__.rst.txt	4952	0644	editdlrm
__main__.rst.txt	535	0644	editdlrm

:mod:`sys` --- System-specific parameters and functions ======================================================= .. module:: sys :synopsis: Access system-specific parameters and functions. This module provides access to some variables used or maintained by the interpreter and to functions that interact strongly with the interpreter. It is always available. .. data:: argv The list of command line arguments passed to a Python script. ``argv[0]`` is the script name (it is operating system dependent whether this is a full pathname or not). If the command was executed using the :option:`-c` command line option to the interpreter, ``argv[0]`` is set to the string ``'-c'``. If no script name was passed to the Python interpreter, ``argv[0]`` is the empty string. To loop over the standard input, or the list of files given on the command line, see the :mod:`fileinput` module. .. data:: byteorder An indicator of the native byte order. This will have the value ``'big'`` on big-endian (most-significant byte first) platforms, and ``'little'`` on little-endian (least-significant byte first) platforms. .. versionadded:: 2.0 .. data:: builtin_module_names A tuple of strings giving the names of all modules that are compiled into this Python interpreter. (This information is not available in any other way --- ``modules.keys()`` only lists the imported modules.) .. function:: call_tracing(func, args) Call ``func(*args)``, while tracing is enabled. The tracing state is saved, and restored afterwards. This is intended to be called from a debugger from a checkpoint, to recursively debug some other code. .. data:: copyright A string containing the copyright pertaining to the Python interpreter. .. function:: _clear_type_cache() Clear the internal type cache. The type cache is used to speed up attribute and method lookups. Use the function *only* to drop unnecessary references during reference leak debugging. This function should be used for internal and specialized purposes only. .. versionadded:: 2.6 .. function:: _current_frames() Return a dictionary mapping each thread's identifier to the topmost stack frame currently active in that thread at the time the function is called. Note that functions in the :mod:`traceback` module can build the call stack given such a frame. This is most useful for debugging deadlock: this function does not require the deadlocked threads' cooperation, and such threads' call stacks are frozen for as long as they remain deadlocked. The frame returned for a non-deadlocked thread may bear no relationship to that thread's current activity by the time calling code examines the frame. This function should be used for internal and specialized purposes only. .. versionadded:: 2.5 .. data:: dllhandle Integer specifying the handle of the Python DLL. Availability: Windows. .. function:: displayhook(value) If *value* is not ``None``, this function prints it to ``sys.stdout``, and saves it in ``__builtin__._``. ``sys.displayhook`` is called on the result of evaluating an :term:`expression` entered in an interactive Python session. The display of these values can be customized by assigning another one-argument function to ``sys.displayhook``. .. data:: dont_write_bytecode If this is true, Python won't try to write ``.pyc`` or ``.pyo`` files on the import of source modules. This value is initially set to ``True`` or ``False`` depending on the :option:`-B` command line option and the :envvar:`PYTHONDONTWRITEBYTECODE` environment variable, but you can set it yourself to control bytecode file generation. .. versionadded:: 2.6 .. function:: excepthook(type, value, traceback) This function prints out a given traceback and exception to ``sys.stderr``. When an exception is raised and uncaught, the interpreter calls ``sys.excepthook`` with three arguments, the exception class, exception instance, and a traceback object. In an interactive session this happens just before control is returned to the prompt; in a Python program this happens just before the program exits. The handling of such top-level exceptions can be customized by assigning another three-argument function to ``sys.excepthook``. .. data:: __displayhook__ __excepthook__ These objects contain the original values of ``displayhook`` and ``excepthook`` at the start of the program. They are saved so that ``displayhook`` and ``excepthook`` can be restored in case they happen to get replaced with broken objects. .. function:: exc_info() This function returns a tuple of three values that give information about the exception that is currently being handled. The information returned is specific both to the current thread and to the current stack frame. If the current stack frame is not handling an exception, the information is taken from the calling stack frame, or its caller, and so on until a stack frame is found that is handling an exception. Here, "handling an exception" is defined as "executing or having executed an except clause." For any stack frame, only information about the most recently handled exception is accessible. .. index:: object: traceback If no exception is being handled anywhere on the stack, a tuple containing three ``None`` values is returned. Otherwise, the values returned are ``(type, value, traceback)``. Their meaning is: *type* gets the exception type of the exception being handled (a class object); *value* gets the exception parameter (its :dfn:`associated value` or the second argument to :keyword:`raise`, which is always a class instance if the exception type is a class object); *traceback* gets a traceback object (see the Reference Manual) which encapsulates the call stack at the point where the exception originally occurred. If :func:`exc_clear` is called, this function will return three ``None`` values until either another exception is raised in the current thread or the execution stack returns to a frame where another exception is being handled. .. warning:: Assigning the *traceback* return value to a local variable in a function that is handling an exception will cause a circular reference. This will prevent anything referenced by a local variable in the same function or by the traceback from being garbage collected. Since most functions don't need access to the traceback, the best solution is to use something like ``exctype, value = sys.exc_info()[:2]`` to extract only the exception type and value. If you do need the traceback, make sure to delete it after use (best done with a :keyword:`try` ... :keyword:`finally` statement) or to call :func:`exc_info` in a function that does not itself handle an exception. .. note:: Beginning with Python 2.2, such cycles are automatically reclaimed when garbage collection is enabled and they become unreachable, but it remains more efficient to avoid creating cycles. .. function:: exc_clear() This function clears all information relating to the current or last exception that occurred in the current thread. After calling this function, :func:`exc_info` will return three ``None`` values until another exception is raised in the current thread or the execution stack returns to a frame where another exception is being handled. This function is only needed in only a few obscure situations. These include logging and error handling systems that report information on the last or current exception. This function can also be used to try to free resources and trigger object finalization, though no guarantee is made as to what objects will be freed, if any. .. versionadded:: 2.3 .. data:: exc_type exc_value exc_traceback .. deprecated:: 1.5 Use :func:`exc_info` instead. Since they are global variables, they are not specific to the current thread, so their use is not safe in a multi-threaded program. When no exception is being handled, ``exc_type`` is set to ``None`` and the other two are undefined. .. data:: exec_prefix A string giving the site-specific directory prefix where the platform-dependent Python files are installed; by default, this is also ``'/usr/local'``. This can be set at build time with the ``--exec-prefix`` argument to the :program:`configure` script. Specifically, all configuration files (e.g. the :file:`pyconfig.h` header file) are installed in the directory :file:`{exec_prefix}/lib/python{X.Y}/config`, and shared library modules are installed in :file:`{exec_prefix}/lib/python{X.Y}/lib-dynload`, where *X.Y* is the version number of Python, for example ``2.7``. .. data:: executable A string giving the absolute path of the executable binary for the Python interpreter, on systems where this makes sense. If Python is unable to retrieve the real path to its executable, :data:`sys.executable` will be an empty string or ``None``. .. function:: exit([arg]) Exit from Python. This is implemented by raising the :exc:`SystemExit` exception, so cleanup actions specified by finally clauses of :keyword:`try` statements are honored, and it is possible to intercept the exit attempt at an outer level. The optional argument *arg* can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered "successful termination" and any nonzero value is considered "abnormal termination" by shells and the like. Most systems require it to be in the range 0--127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors. If another type of object is passed, ``None`` is equivalent to passing zero, and any other object is printed to :data:`stderr` and results in an exit code of 1. In particular, ``sys.exit("some error message")`` is a quick way to exit a program when an error occurs. Since :func:`exit` ultimately "only" raises an exception, it will only exit the process when called from the main thread, and the exception is not intercepted. .. data:: exitfunc This value is not actually defined by the module, but can be set by the user (or by a program) to specify a clean-up action at program exit. When set, it should be a parameterless function. This function will be called when the interpreter exits. Only one function may be installed in this way; to allow multiple functions which will be called at termination, use the :mod:`atexit` module. .. note:: The exit function is not called when the program is killed by a signal, when a Python fatal internal error is detected, or when ``os._exit()`` is called. .. deprecated:: 2.4 Use :mod:`atexit` instead. .. data:: flags The struct sequence *flags* exposes the status of command line flags. The attributes are read only. ============================= =================================== attribute flag ============================= =================================== :const:`debug` :option:`-d` :const:`py3k_warning` :option:`-3` :const:`division_warning` :option:`-Q` :const:`division_new` :option:`-Qnew <-Q>` :const:`inspect` :option:`-i` :const:`interactive` :option:`-i` :const:`optimize` :option:`-O` or :option:`-OO` :const:`dont_write_bytecode` :option:`-B` :const:`no_user_site` :option:`-s` :const:`no_site` :option:`-S` :const:`ignore_environment` :option:`-E` :const:`tabcheck` :option:`-t` or :option:`-tt <-t>` :const:`verbose` :option:`-v` :const:`unicode` :option:`-U` :const:`bytes_warning` :option:`-b` :const:`hash_randomization` :option:`-R` ============================= =================================== .. versionadded:: 2.6 .. versionadded:: 2.7.3 The ``hash_randomization`` attribute. .. data:: float_info A structseq holding information about the float type. It contains low level information about the precision and internal representation. The values correspond to the various floating-point constants defined in the standard header file :file:`float.h` for the 'C' programming language; see section 5.2.4.2.2 of the 1999 ISO/IEC C standard [C99]_, 'Characteristics of floating types', for details. .. tabularcolumns:: |l|l|L| +---------------------+----------------+--------------------------------------------------+ | attribute | float.h macro | explanation | +=====================+================+==================================================+ | :const:`epsilon` | DBL_EPSILON | difference between 1 and the least value greater | | | | than 1 that is representable as a float | +---------------------+----------------+--------------------------------------------------+ | :const:`dig` | DBL_DIG | maximum number of decimal digits that can be | | | | faithfully represented in a float; see below | +---------------------+----------------+--------------------------------------------------+ | :const:`mant_dig` | DBL_MANT_DIG | float precision: the number of base-``radix`` | | | | digits in the significand of a float | +---------------------+----------------+--------------------------------------------------+ | :const:`max` | DBL_MAX | maximum representable finite float | +---------------------+----------------+--------------------------------------------------+ | :const:`max_exp` | DBL_MAX_EXP | maximum integer e such that ``radix**(e-1)`` is | | | | a representable finite float | +---------------------+----------------+--------------------------------------------------+ | :const:`max_10_exp` | DBL_MAX_10_EXP | maximum integer e such that ``10**e`` is in the | | | | range of representable finite floats | +---------------------+----------------+--------------------------------------------------+ | :const:`min` | DBL_MIN | minimum positive normalized float | +---------------------+----------------+--------------------------------------------------+ | :const:`min_exp` | DBL_MIN_EXP | minimum integer e such that ``radix**(e-1)`` is | | | | a normalized float | +---------------------+----------------+--------------------------------------------------+ | :const:`min_10_exp` | DBL_MIN_10_EXP | minimum integer e such that ``10**e`` is a | | | | normalized float | +---------------------+----------------+--------------------------------------------------+ | :const:`radix` | FLT_RADIX | radix of exponent representation | +---------------------+----------------+--------------------------------------------------+ | :const:`rounds` | FLT_ROUNDS | integer constant representing the rounding mode | | | | used for arithmetic operations. This reflects | | | | the value of the system FLT_ROUNDS macro at | | | | interpreter startup time. See section 5.2.4.2.2 | | | | of the C99 standard for an explanation of the | | | | possible values and their meanings. | +---------------------+----------------+--------------------------------------------------+ The attribute :attr:`sys.float_info.dig` needs further explanation. If ``s`` is any string representing a decimal number with at most :attr:`sys.float_info.dig` significant digits, then converting ``s`` to a float and back again will recover a string representing the same decimal value:: >>> import sys >>> sys.float_info.dig 15 >>> s = '3.14159265358979' # decimal string with 15 significant digits >>> format(float(s), '.15g') # convert to float and back -> same value '3.14159265358979' But for strings with more than :attr:`sys.float_info.dig` significant digits, this isn't always true:: >>> s = '9876543211234567' # 16 significant digits is too many! >>> format(float(s), '.16g') # conversion changes value '9876543211234568' .. versionadded:: 2.6 .. data:: float_repr_style A string indicating how the :func:`repr` function behaves for floats. If the string has value ``'short'`` then for a finite float ``x``, ``repr(x)`` aims to produce a short string with the property that ``float(repr(x)) == x``. This is the usual behaviour in Python 2.7 and later. Otherwise, ``float_repr_style`` has value ``'legacy'`` and ``repr(x)`` behaves in the same way as it did in versions of Python prior to 2.7. .. versionadded:: 2.7 .. function:: getcheckinterval() Return the interpreter's "check interval"; see :func:`setcheckinterval`. .. versionadded:: 2.3 .. function:: getdefaultencoding() Return the name of the current default string encoding used by the Unicode implementation. .. versionadded:: 2.0 .. function:: getdlopenflags() Return the current value of the flags that are used for :c:func:`dlopen` calls. The flag constants are defined in the :mod:`dl` and :mod:`DLFCN` modules. Availability: Unix. .. versionadded:: 2.2 .. function:: getfilesystemencoding() Return the name of the encoding used to convert Unicode filenames into system file names, or ``None`` if the system default encoding is used. The result value depends on the operating system: * On Mac OS X, the encoding is ``'utf-8'``. * On Unix, the encoding is the user's preference according to the result of nl_langinfo(CODESET), or ``None`` if the ``nl_langinfo(CODESET)`` failed. * On Windows NT+, file names are Unicode natively, so no conversion is performed. :func:`getfilesystemencoding` still returns ``'mbcs'``, as this is the encoding that applications should use when they explicitly want to convert Unicode strings to byte strings that are equivalent when used as file names. * On Windows 9x, the encoding is ``'mbcs'``. .. versionadded:: 2.3 .. function:: getrefcount(object) Return the reference count of the *object*. The count returned is generally one higher than you might expect, because it includes the (temporary) reference as an argument to :func:`getrefcount`. .. function:: getrecursionlimit() Return the current value of the recursion limit, the maximum depth of the Python interpreter stack. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python. It can be set by :func:`setrecursionlimit`. .. function:: getsizeof(object[, default]) Return the size of an object in bytes. The object can be any type of object. All built-in objects will return correct results, but this does not have to hold true for third-party extensions as it is implementation specific. If given, *default* will be returned if the object does not provide means to retrieve the size. Otherwise a :exc:`TypeError` will be raised. :func:`getsizeof` calls the object's ``__sizeof__`` method and adds an additional garbage collector overhead if the object is managed by the garbage collector. .. versionadded:: 2.6 .. function:: _getframe([depth]) Return a frame object from the call stack. If optional integer *depth* is given, return the frame object that many calls below the top of the stack. If that is deeper than the call stack, :exc:`ValueError` is raised. The default for *depth* is zero, returning the frame at the top of the call stack. .. impl-detail:: This function should be used for internal and specialized purposes only. It is not guaranteed to exist in all implementations of Python. .. function:: getprofile() .. index:: single: profile function single: profiler Get the profiler function as set by :func:`setprofile`. .. versionadded:: 2.6 .. function:: gettrace() .. index:: single: trace function single: debugger Get the trace function as set by :func:`settrace`. .. impl-detail:: The :func:`gettrace` function is intended only for implementing debuggers, profilers, coverage tools and the like. Its behavior is part of the implementation platform, rather than part of the language definition, and thus may not be available in all Python implementations. .. versionadded:: 2.6 .. function:: getwindowsversion() Return a named tuple describing the Windows version currently running. The named elements are *major*, *minor*, *build*, *platform*, *service_pack*, *service_pack_minor*, *service_pack_major*, *suite_mask*, and *product_type*. *service_pack* contains a string while all other values are integers. The components can also be accessed by name, so ``sys.getwindowsversion()[0]`` is equivalent to ``sys.getwindowsversion().major``. For compatibility with prior versions, only the first 5 elements are retrievable by indexing. *platform* may be one of the following values: +-----------------------------------------+-------------------------+ | Constant | Platform | +=========================================+=========================+ | :const:`0 (VER_PLATFORM_WIN32s)` | Win32s on Windows 3.1 | +-----------------------------------------+-------------------------+ | :const:`1 (VER_PLATFORM_WIN32_WINDOWS)` | Windows 95/98/ME | +-----------------------------------------+-------------------------+ | :const:`2 (VER_PLATFORM_WIN32_NT)` | Windows NT/2000/XP/x64 | +-----------------------------------------+-------------------------+ | :const:`3 (VER_PLATFORM_WIN32_CE)` | Windows CE | +-----------------------------------------+-------------------------+ *product_type* may be one of the following values: +---------------------------------------+---------------------------------+ | Constant | Meaning | +=======================================+=================================+ | :const:`1 (VER_NT_WORKSTATION)` | The system is a workstation. | +---------------------------------------+---------------------------------+ | :const:`2 (VER_NT_DOMAIN_CONTROLLER)` | The system is a domain | | | controller. | +---------------------------------------+---------------------------------+ | :const:`3 (VER_NT_SERVER)` | The system is a server, but not | | | a domain controller. | +---------------------------------------+---------------------------------+ This function wraps the Win32 :c:func:`GetVersionEx` function; see the Microsoft documentation on :c:func:`OSVERSIONINFOEX` for more information about these fields. Availability: Windows. .. versionadded:: 2.3 .. versionchanged:: 2.7 Changed to a named tuple and added *service_pack_minor*, *service_pack_major*, *suite_mask*, and *product_type*. .. data:: hexversion The version number encoded as a single integer. This is guaranteed to increase with each version, including proper support for non-production releases. For example, to test that the Python interpreter is at least version 1.5.2, use:: if sys.hexversion >= 0x010502F0: # use some advanced feature ... else: # use an alternative implementation or warn the user ... This is called ``hexversion`` since it only really looks meaningful when viewed as the result of passing it to the built-in :func:`hex` function. The ``version_info`` value may be used for a more human-friendly encoding of the same information. The ``hexversion`` is a 32-bit number with the following layout: +-------------------------+------------------------------------------------+ | Bits (big endian order) | Meaning | +=========================+================================================+ | :const:`1-8` | ``PY_MAJOR_VERSION`` (the ``2`` in | | | ``2.1.0a3``) | +-------------------------+------------------------------------------------+ | :const:`9-16` | ``PY_MINOR_VERSION`` (the ``1`` in | | | ``2.1.0a3``) | +-------------------------+------------------------------------------------+ | :const:`17-24` | ``PY_MICRO_VERSION`` (the ``0`` in | | | ``2.1.0a3``) | +-------------------------+------------------------------------------------+ | :const:`25-28` | ``PY_RELEASE_LEVEL`` (``0xA`` for alpha, | | | ``0xB`` for beta, ``0xC`` for release | | | candidate and ``0xF`` for final) | +-------------------------+------------------------------------------------+ | :const:`29-32` | ``PY_RELEASE_SERIAL`` (the ``3`` in | | | ``2.1.0a3``, zero for final releases) | +-------------------------+------------------------------------------------+ Thus ``2.1.0a3`` is hexversion ``0x020100a3``. .. versionadded:: 1.5.2 .. data:: long_info A struct sequence that holds information about Python's internal representation of integers. The attributes are read only. .. tabularcolumns:: |l|L| +-------------------------+----------------------------------------------+ | Attribute | Explanation | +=========================+==============================================+ | :const:`bits_per_digit` | number of bits held in each digit. Python | | | integers are stored internally in base | | | ``2**long_info.bits_per_digit`` | +-------------------------+----------------------------------------------+ | :const:`sizeof_digit` | size in bytes of the C type used to | | | represent a digit | +-------------------------+----------------------------------------------+ .. versionadded:: 2.7 .. data:: last_type last_value last_traceback These three variables are not always defined; they are set when an exception is not handled and the interpreter prints an error message and a stack traceback. Their intended use is to allow an interactive user to import a debugger module and engage in post-mortem debugging without having to re-execute the command that caused the error. (Typical use is ``import pdb; pdb.pm()`` to enter the post-mortem debugger; see chapter :ref:`debugger` for more information.) The meaning of the variables is the same as that of the return values from :func:`exc_info` above. (Since there is only one interactive thread, thread-safety is not a concern for these variables, unlike for ``exc_type`` etc.) .. data:: maxint The largest positive integer supported by Python's regular integer type. This is at least 2\*\*31-1. The largest negative integer is ``-maxint-1`` --- the asymmetry results from the use of 2's complement binary arithmetic. .. data:: maxsize The largest positive integer supported by the platform's Py_ssize_t type, and thus the maximum size lists, strings, dicts, and many other containers can have. .. data:: maxunicode An integer giving the largest supported code point for a Unicode character. The value of this depends on the configuration option that specifies whether Unicode characters are stored as UCS-2 or UCS-4. .. data:: meta_path A list of :term:`finder` objects that have their :meth:`find_module` methods called to see if one of the objects can find the module to be imported. The :meth:`find_module` method is called at least with the absolute name of the module being imported. If the module to be imported is contained in package then the parent package's :attr:`__path__` attribute is passed in as a second argument. The method returns ``None`` if the module cannot be found, else returns a :term:`loader`. :data:`sys.meta_path` is searched before any implicit default finders or :data:`sys.path`. See :pep:`302` for the original specification. .. data:: modules .. index:: builtin: reload This is a dictionary that maps module names to modules which have already been loaded. This can be manipulated to force reloading of modules and other tricks. Note that removing a module from this dictionary is *not* the same as calling :func:`reload` on the corresponding module object. .. data:: path .. index:: triple: module; search; path A list of strings that specifies the search path for modules. Initialized from the environment variable :envvar:`PYTHONPATH`, plus an installation-dependent default. As initialized upon program startup, the first item of this list, ``path[0]``, is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), ``path[0]`` is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted *before* the entries inserted as a result of :envvar:`PYTHONPATH`. A program is free to modify this list for its own purposes. .. versionchanged:: 2.3 Unicode strings are no longer ignored. .. seealso:: Module :mod:`site` This describes how to use .pth files to extend :data:`sys.path`. .. data:: path_hooks A list of callables that take a path argument to try to create a :term:`finder` for the path. If a finder can be created, it is to be returned by the callable, else raise :exc:`ImportError`. Originally specified in :pep:`302`. .. data:: path_importer_cache A dictionary acting as a cache for :term:`finder` objects. The keys are paths that have been passed to :data:`sys.path_hooks` and the values are the finders that are found. If a path is a valid file system path but no explicit finder is found on :data:`sys.path_hooks` then ``None`` is stored to represent the implicit default finder should be used. If the path is not an existing path then :class:`imp.NullImporter` is set. Originally specified in :pep:`302`. .. data:: platform This string contains a platform identifier that can be used to append platform-specific components to :data:`sys.path`, for instance. For most Unix systems, this is the lowercased OS name as returned by ``uname -s`` with the first part of the version as returned by ``uname -r`` appended, e.g. ``'sunos5'``, *at the time when Python was built*. Unless you want to test for a specific system version, it is therefore recommended to use the following idiom:: if sys.platform.startswith('freebsd'): # FreeBSD-specific code here... elif sys.platform.startswith('linux'): # Linux-specific code here... .. versionchanged:: 2.7.3 Since lots of code check for ``sys.platform == 'linux2'``, and there is no essential change between Linux 2.x and 3.x, ``sys.platform`` is always set to ``'linux2'``, even on Linux 3.x. In Python 3.3 and later, the value will always be set to ``'linux'``, so it is recommended to always use the ``startswith`` idiom presented above. For other systems, the values are: ===================== =========================== System :data:`platform` value ===================== =========================== Linux (2.x *and* 3.x) ``'linux2'`` Windows ``'win32'`` Windows/Cygwin ``'cygwin'`` Mac OS X ``'darwin'`` OS/2 ``'os2'`` OS/2 EMX ``'os2emx'`` RiscOS ``'riscos'`` AtheOS ``'atheos'`` ===================== =========================== .. seealso:: :attr:`os.name` has a coarser granularity. :func:`os.uname` gives system-dependent version information. The :mod:`platform` module provides detailed checks for the system's identity. .. data:: prefix A string giving the site-specific directory prefix where the platform independent Python files are installed; by default, this is the string ``'/usr/local'``. This can be set at build time with the ``--prefix`` argument to the :program:`configure` script. The main collection of Python library modules is installed in the directory :file:`{prefix}/lib/python{X.Y}` while the platform independent header files (all except :file:`pyconfig.h`) are stored in :file:`{prefix}/include/python{X.Y}`, where *X.Y* is the version number of Python, for example ``2.7``. .. data:: ps1 ps2 .. index:: single: interpreter prompts single: prompts, interpreter Strings specifying the primary and secondary prompt of the interpreter. These are only defined if the interpreter is in interactive mode. Their initial values in this case are ``'>>> '`` and ``'... '``. If a non-string object is assigned to either variable, its :func:`str` is re-evaluated each time the interpreter prepares to read a new interactive command; this can be used to implement a dynamic prompt. .. data:: py3kwarning Bool containing the status of the Python 3 warning flag. It's ``True`` when Python is started with the -3 option. (This should be considered read-only; setting it to a different value doesn't have an effect on Python 3 warnings.) .. versionadded:: 2.6 .. function:: setcheckinterval(interval) Set the interpreter's "check interval". This integer value determines how often the interpreter checks for periodic things such as thread switches and signal handlers. The default is ``100``, meaning the check is performed every 100 Python virtual instructions. Setting it to a larger value may increase performance for programs using threads. Setting it to a value ``<=`` 0 checks every virtual instruction, maximizing responsiveness as well as overhead. .. function:: setdefaultencoding(name) Set the current default string encoding used by the Unicode implementation. If *name* does not match any available encoding, :exc:`LookupError` is raised. This function is only intended to be used by the :mod:`site` module implementation and, where needed, by :mod:`sitecustomize`. Once used by the :mod:`site` module, it is removed from the :mod:`sys` module's namespace. .. Note that :mod:`site` is not imported if the :option:`-S` option is passed to the interpreter, in which case this function will remain available. .. versionadded:: 2.0 .. function:: setdlopenflags(n) Set the flags used by the interpreter for :c:func:`dlopen` calls, such as when the interpreter loads extension modules. Among other things, this will enable a lazy resolving of symbols when importing a module, if called as ``sys.setdlopenflags(0)``. To share symbols across extension modules, call as ``sys.setdlopenflags(dl.RTLD_NOW | dl.RTLD_GLOBAL)``. Symbolic names for the flag modules can be either found in the :mod:`dl` module, or in the :mod:`DLFCN` module. If :mod:`DLFCN` is not available, it can be generated from :file:`/usr/include/dlfcn.h` using the :program:`h2py` script. Availability: Unix. .. versionadded:: 2.2 .. function:: setprofile(profilefunc) .. index:: single: profile function single: profiler Set the system's profile function, which allows you to implement a Python source code profiler in Python. See chapter :ref:`profile` for more information on the Python profiler. The system's profile function is called similarly to the system's trace function (see :func:`settrace`), but it is called with different events, for example it isn't called for each executed line of code (only on call and return, but the return event is reported even when an exception has been set). The function is thread-specific, but there is no way for the profiler to know about context switches between threads, so it does not make sense to use this in the presence of multiple threads. Also, its return value is not used, so it can simply return ``None``. Profile functions should have three arguments: *frame*, *event*, and *arg*. *frame* is the current stack frame. *event* is a string: ``'call'``, ``'return'``, ``'c_call'``, ``'c_return'``, or ``'c_exception'``. *arg* depends on the event type. The events have the following meaning: ``'call'`` A function is called (or some other code block entered). The profile function is called; *arg* is ``None``. ``'return'`` A function (or other code block) is about to return. The profile function is called; *arg* is the value that will be returned, or ``None`` if the event is caused by an exception being raised. ``'c_call'`` A C function is about to be called. This may be an extension function or a built-in. *arg* is the C function object. ``'c_return'`` A C function has returned. *arg* is the C function object. ``'c_exception'`` A C function has raised an exception. *arg* is the C function object. .. function:: setrecursionlimit(limit) Set the maximum depth of the Python interpreter stack to *limit*. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python. The highest possible limit is platform-dependent. A user may need to set the limit higher when she has a program that requires deep recursion and a platform that supports a higher limit. This should be done with care, because a too-high limit can lead to a crash. .. function:: settrace(tracefunc) .. index:: single: trace function single: debugger Set the system's trace function, which allows you to implement a Python source code debugger in Python. The function is thread-specific; for a debugger to support multiple threads, it must be registered using :func:`settrace` for each thread being debugged. Trace functions should have three arguments: *frame*, *event*, and *arg*. *frame* is the current stack frame. *event* is a string: ``'call'``, ``'line'``, ``'return'`` or ``'exception'``. *arg* depends on the event type. The trace function is invoked (with *event* set to ``'call'``) whenever a new local scope is entered; it should return a reference to a local trace function to be used that scope, or ``None`` if the scope shouldn't be traced. The local trace function should return a reference to itself (or to another function for further tracing in that scope), or ``None`` to turn off tracing in that scope. The events have the following meaning: ``'call'`` A function is called (or some other code block entered). The global trace function is called; *arg* is ``None``; the return value specifies the local trace function. ``'line'`` The interpreter is about to execute a new line of code or re-execute the condition of a loop. The local trace function is called; *arg* is ``None``; the return value specifies the new local trace function. See :file:`Objects/lnotab_notes.txt` for a detailed explanation of how this works. ``'return'`` A function (or other code block) is about to return. The local trace function is called; *arg* is the value that will be returned, or ``None`` if the event is caused by an exception being raised. The trace function's return value is ignored. ``'exception'`` An exception has occurred. The local trace function is called; *arg* is a tuple ``(exception, value, traceback)``; the return value specifies the new local trace function. Note that as an exception is propagated down the chain of callers, an ``'exception'`` event is generated at each level. For more information on code and frame objects, refer to :ref:`types`. .. impl-detail:: The :func:`settrace` function is intended only for implementing debuggers, profilers, coverage tools and the like. Its behavior is part of the implementation platform, rather than part of the language definition, and thus may not be available in all Python implementations. .. function:: settscdump(on_flag) Activate dumping of VM measurements using the Pentium timestamp counter, if *on_flag* is true. Deactivate these dumps if *on_flag* is off. The function is available only if Python was compiled with ``--with-tsc``. To understand the output of this dump, read :file:`Python/ceval.c` in the Python sources. .. versionadded:: 2.4 .. impl-detail:: This function is intimately bound to CPython implementation details and thus not likely to be implemented elsewhere. .. data:: stdin stdout stderr .. index:: builtin: input builtin: raw_input File objects corresponding to the interpreter's standard input, output and error streams. ``stdin`` is used for all interpreter input except for scripts but including calls to :func:`input` and :func:`raw_input`. ``stdout`` is used for the output of :keyword:`print` and :term:`expression` statements and for the prompts of :func:`input` and :func:`raw_input`. The interpreter's own prompts and (almost all of) its error messages go to ``stderr``. ``stdout`` and ``stderr`` needn't be built-in file objects: any object is acceptable as long as it has a :meth:`write` method that takes a string argument. (Changing these objects doesn't affect the standard I/O streams of processes executed by :func:`os.popen`, :func:`os.system` or the :func:`exec\*` family of functions in the :mod:`os` module.) .. data:: __stdin__ __stdout__ __stderr__ These objects contain the original values of ``stdin``, ``stderr`` and ``stdout`` at the start of the program. They are used during finalization, and could be useful to print to the actual standard stream no matter if the ``sys.std*`` object has been redirected. It can also be used to restore the actual files to known working file objects in case they have been overwritten with a broken object. However, the preferred way to do this is to explicitly save the previous stream before replacing it, and restore the saved object. .. data:: subversion A triple (repo, branch, version) representing the Subversion information of the Python interpreter. *repo* is the name of the repository, ``'CPython'``. *branch* is a string of one of the forms ``'trunk'``, ``'branches/name'`` or ``'tags/name'``. *version* is the output of ``svnversion``, if the interpreter was built from a Subversion checkout; it contains the revision number (range) and possibly a trailing 'M' if there were local modifications. If the tree was exported (or svnversion was not available), it is the revision of ``Include/patchlevel.h`` if the branch is a tag. Otherwise, it is ``None``. .. versionadded:: 2.5 .. note:: Python is now `developed `_ using Mercurial. In recent Python 2.7 bugfix releases, :data:`subversion` therefore contains placeholder information. It is removed in Python 3.3. .. data:: tracebacklimit When this variable is set to an integer value, it determines the maximum number of levels of traceback information printed when an unhandled exception occurs. The default is ``1000``. When set to ``0`` or less, all traceback information is suppressed and only the exception type and value are printed. .. data:: version A string containing the version number of the Python interpreter plus additional information on the build number and compiler used. This string is displayed when the interactive interpreter is started. Do not extract version information out of it, rather, use :data:`version_info` and the functions provided by the :mod:`platform` module. .. data:: api_version The C API version for this interpreter. Programmers may find this useful when debugging version conflicts between Python and extension modules. .. versionadded:: 2.3 .. data:: version_info A tuple containing the five components of the version number: *major*, *minor*, *micro*, *releaselevel*, and *serial*. All values except *releaselevel* are integers; the release level is ``'alpha'``, ``'beta'``, ``'candidate'``, or ``'final'``. The ``version_info`` value corresponding to the Python version 2.0 is ``(2, 0, 0, 'final', 0)``. The components can also be accessed by name, so ``sys.version_info[0]`` is equivalent to ``sys.version_info.major`` and so on. .. versionadded:: 2.0 .. versionchanged:: 2.7 Added named component attributes .. data:: warnoptions This is an implementation detail of the warnings framework; do not modify this value. Refer to the :mod:`warnings` module for more information on the warnings framework. .. data:: winver The version number used to form registry keys on Windows platforms. This is stored as string resource 1000 in the Python DLL. The value is normally the first three characters of :const:`version`. It is provided in the :mod:`sys` module for informational purposes; modifying this value has no effect on the registry keys used by Python. Availability: Windows. .. rubric:: Citations .. [C99] ISO/IEC 9899:1999. "Programming languages -- C." A public draft of this standard is available at http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf\ .