2
:mod:`sys` --- System-specific parameters and functions
3
=======================================================
6
:synopsis: Access system-specific parameters and functions.
9
This module provides access to some variables used or maintained by the
10
interpreter and to functions that interact strongly with the interpreter. It is
16
The list of command line arguments passed to a Python script. ``argv[0]`` is the
17
script name (it is operating system dependent whether this is a full pathname or
18
not). If the command was executed using the :option:`-c` command line option to
19
the interpreter, ``argv[0]`` is set to the string ``'-c'``. If no script name
20
was passed to the Python interpreter, ``argv[0]`` is the empty string.
22
To loop over the standard input, or the list of files given on the
23
command line, see the :mod:`fileinput` module.
28
An indicator of the native byte order. This will have the value ``'big'`` on
29
big-endian (most-significant byte first) platforms, and ``'little'`` on
30
little-endian (least-significant byte first) platforms.
37
A triple (repo, branch, version) representing the Subversion information of the
38
Python interpreter. *repo* is the name of the repository, ``'CPython'``.
39
*branch* is a string of one of the forms ``'trunk'``, ``'branches/name'`` or
40
``'tags/name'``. *version* is the output of ``svnversion``, if the interpreter
41
was built from a Subversion checkout; it contains the revision number (range)
42
and possibly a trailing 'M' if there were local modifications. If the tree was
43
exported (or svnversion was not available), it is the revision of
44
``Include/patchlevel.h`` if the branch is a tag. Otherwise, it is ``None``.
49
.. data:: builtin_module_names
51
A tuple of strings giving the names of all modules that are compiled into this
52
Python interpreter. (This information is not available in any other way ---
53
``modules.keys()`` only lists the imported modules.)
58
A string containing the copyright pertaining to the Python interpreter.
61
.. function:: _clear_type_cache()
63
Clear the internal type cache. The type cache is used to speed up attribute
64
and method lookups. Use the function *only* to drop unnecessary references
65
during reference leak debugging.
67
This function should be used for internal and specialized purposes only.
72
.. function:: _current_frames()
74
Return a dictionary mapping each thread's identifier to the topmost stack frame
75
currently active in that thread at the time the function is called. Note that
76
functions in the :mod:`traceback` module can build the call stack given such a
79
This is most useful for debugging deadlock: this function does not require the
80
deadlocked threads' cooperation, and such threads' call stacks are frozen for as
81
long as they remain deadlocked. The frame returned for a non-deadlocked thread
82
may bear no relationship to that thread's current activity by the time calling
83
code examines the frame.
85
This function should be used for internal and specialized purposes only.
92
Integer specifying the handle of the Python DLL. Availability: Windows.
95
.. function:: displayhook(value)
97
If *value* is not ``None``, this function prints it to ``sys.stdout``, and saves
98
it in ``__builtin__._``.
100
``sys.displayhook`` is called on the result of evaluating an :term:`expression`
101
entered in an interactive Python session. The display of these values can be
102
customized by assigning another one-argument function to ``sys.displayhook``.
105
.. function:: excepthook(type, value, traceback)
107
This function prints out a given traceback and exception to ``sys.stderr``.
109
When an exception is raised and uncaught, the interpreter calls
110
``sys.excepthook`` with three arguments, the exception class, exception
111
instance, and a traceback object. In an interactive session this happens just
112
before control is returned to the prompt; in a Python program this happens just
113
before the program exits. The handling of such top-level exceptions can be
114
customized by assigning another three-argument function to ``sys.excepthook``.
117
.. data:: __displayhook__
120
These objects contain the original values of ``displayhook`` and ``excepthook``
121
at the start of the program. They are saved so that ``displayhook`` and
122
``excepthook`` can be restored in case they happen to get replaced with broken
126
.. function:: exc_info()
128
This function returns a tuple of three values that give information about the
129
exception that is currently being handled. The information returned is specific
130
both to the current thread and to the current stack frame. If the current stack
131
frame is not handling an exception, the information is taken from the calling
132
stack frame, or its caller, and so on until a stack frame is found that is
133
handling an exception. Here, "handling an exception" is defined as "executing
134
or having executed an except clause." For any stack frame, only information
135
about the most recently handled exception is accessible.
137
.. index:: object: traceback
139
If no exception is being handled anywhere on the stack, a tuple containing three
140
``None`` values is returned. Otherwise, the values returned are ``(type, value,
141
traceback)``. Their meaning is: *type* gets the exception type of the exception
142
being handled (a class object); *value* gets the exception parameter (its
143
:dfn:`associated value` or the second argument to :keyword:`raise`, which is
144
always a class instance if the exception type is a class object); *traceback*
145
gets a traceback object (see the Reference Manual) which encapsulates the call
146
stack at the point where the exception originally occurred.
148
If :func:`exc_clear` is called, this function will return three ``None`` values
149
until either another exception is raised in the current thread or the execution
150
stack returns to a frame where another exception is being handled.
154
Assigning the *traceback* return value to a local variable in a function that is
155
handling an exception will cause a circular reference. This will prevent
156
anything referenced by a local variable in the same function or by the traceback
157
from being garbage collected. Since most functions don't need access to the
158
traceback, the best solution is to use something like ``exctype, value =
159
sys.exc_info()[:2]`` to extract only the exception type and value. If you do
160
need the traceback, make sure to delete it after use (best done with a
161
:keyword:`try` ... :keyword:`finally` statement) or to call :func:`exc_info` in
162
a function that does not itself handle an exception.
166
Beginning with Python 2.2, such cycles are automatically reclaimed when garbage
167
collection is enabled and they become unreachable, but it remains more efficient
168
to avoid creating cycles.
171
.. function:: exc_clear()
173
This function clears all information relating to the current or last exception
174
that occurred in the current thread. After calling this function,
175
:func:`exc_info` will return three ``None`` values until another exception is
176
raised in the current thread or the execution stack returns to a frame where
177
another exception is being handled.
179
This function is only needed in only a few obscure situations. These include
180
logging and error handling systems that report information on the last or
181
current exception. This function can also be used to try to free resources and
182
trigger object finalization, though no guarantee is made as to what objects will
185
.. versionadded:: 2.3
193
Use :func:`exc_info` instead.
195
Since they are global variables, they are not specific to the current thread, so
196
their use is not safe in a multi-threaded program. When no exception is being
197
handled, ``exc_type`` is set to ``None`` and the other two are undefined.
200
.. data:: exec_prefix
202
A string giving the site-specific directory prefix where the platform-dependent
203
Python files are installed; by default, this is also ``'/usr/local'``. This can
204
be set at build time with the :option:`--exec-prefix` argument to the
205
:program:`configure` script. Specifically, all configuration files (e.g. the
206
:file:`pyconfig.h` header file) are installed in the directory ``exec_prefix +
207
'/lib/pythonversion/config'``, and shared library modules are installed in
208
``exec_prefix + '/lib/pythonversion/lib-dynload'``, where *version* is equal to
214
A string giving the name of the executable binary for the Python interpreter, on
215
systems where this makes sense.
218
.. function:: exit([arg])
220
Exit from Python. This is implemented by raising the :exc:`SystemExit`
221
exception, so cleanup actions specified by finally clauses of :keyword:`try`
222
statements are honored, and it is possible to intercept the exit attempt at an
223
outer level. The optional argument *arg* can be an integer giving the exit
224
status (defaulting to zero), or another type of object. If it is an integer,
225
zero is considered "successful termination" and any nonzero value is considered
226
"abnormal termination" by shells and the like. Most systems require it to be in
227
the range 0-127, and produce undefined results otherwise. Some systems have a
228
convention for assigning specific meanings to specific exit codes, but these are
229
generally underdeveloped; Unix programs generally use 2 for command line syntax
230
errors and 1 for all other kind of errors. If another type of object is passed,
231
``None`` is equivalent to passing zero, and any other object is printed to
232
``sys.stderr`` and results in an exit code of 1. In particular,
233
``sys.exit("some error message")`` is a quick way to exit a program when an
239
This value is not actually defined by the module, but can be set by the user (or
240
by a program) to specify a clean-up action at program exit. When set, it should
241
be a parameterless function. This function will be called when the interpreter
242
exits. Only one function may be installed in this way; to allow multiple
243
functions which will be called at termination, use the :mod:`atexit` module.
247
The exit function is not called when the program is killed by a signal, when a
248
Python fatal internal error is detected, or when ``os._exit()`` is called.
251
Use :mod:`atexit` instead.
256
The struct sequence *flags* exposes the status of command line flags. The
257
attributes are read only.
259
+------------------------------+------------------------------------------+
261
+==============================+==========================================+
262
| :const:`debug` | -d |
263
+------------------------------+------------------------------------------+
264
| :const:`py3k_warning` | -3 |
265
+------------------------------+------------------------------------------+
266
| :const:`division_warning` | -Q |
267
+------------------------------+------------------------------------------+
268
| :const:`division_new` | -Qnew |
269
+------------------------------+------------------------------------------+
270
| :const:`inspect` | -i |
271
+------------------------------+------------------------------------------+
272
| :const:`interactive` | -i |
273
+------------------------------+------------------------------------------+
274
| :const:`optimize` | -O or -OO |
275
+------------------------------+------------------------------------------+
276
| :const:`dont_write_bytecode` | -B |
277
+------------------------------+------------------------------------------+
278
| :const:`no_site` | -S |
279
+------------------------------+------------------------------------------+
280
| :const:`ignore_environment` | -E |
281
+------------------------------+------------------------------------------+
282
| :const:`tabcheck` | -t or -tt |
283
+------------------------------+------------------------------------------+
284
| :const:`verbose` | -v |
285
+------------------------------+------------------------------------------+
286
| :const:`unicode` | -U |
287
+------------------------------+------------------------------------------+
289
.. versionadded:: 2.6
294
A structseq holding information about the float type. It contains low level
295
information about the precision and internal representation. Please study
296
your system's :file:`float.h` for more information.
298
+---------------------+--------------------------------------------------+
299
| attribute | explanation |
300
+=====================+==================================================+
301
| :const:`epsilon` | Difference between 1 and the next representable |
302
| | floating point number |
303
+---------------------+--------------------------------------------------+
304
| :const:`dig` | digits (see :file:`float.h`) |
305
+---------------------+--------------------------------------------------+
306
| :const:`mant_dig` | mantissa digits (see :file:`float.h`) |
307
+---------------------+--------------------------------------------------+
308
| :const:`max` | maximum representable finite float |
309
+---------------------+--------------------------------------------------+
310
| :const:`max_exp` | maximum int e such that radix**(e-1) is in the |
311
| | range of finite representable floats |
312
+---------------------+--------------------------------------------------+
313
| :const:`max_10_exp` | maximum int e such that 10**e is in the |
314
| | range of finite representable floats |
315
+---------------------+--------------------------------------------------+
316
| :const:`min` | Minimum positive normalizer float |
317
+---------------------+--------------------------------------------------+
318
| :const:`min_exp` | minimum int e such that radix**(e-1) is a |
319
| | normalized float |
320
+---------------------+--------------------------------------------------+
321
| :const:`min_10_exp` | minimum int e such that 10**e is a normalized |
323
+---------------------+--------------------------------------------------+
324
| :const:`radix` | radix of exponent |
325
+---------------------+--------------------------------------------------+
326
| :const:`rounds` | addition rounds (see :file:`float.h`) |
327
+---------------------+--------------------------------------------------+
331
The information in the table is simplified.
333
.. versionadded:: 2.6
336
.. function:: getcheckinterval()
338
Return the interpreter's "check interval"; see :func:`setcheckinterval`.
340
.. versionadded:: 2.3
343
.. function:: getdefaultencoding()
345
Return the name of the current default string encoding used by the Unicode
348
.. versionadded:: 2.0
351
.. function:: getdlopenflags()
353
Return the current value of the flags that are used for :cfunc:`dlopen` calls.
354
The flag constants are defined in the :mod:`dl` and :mod:`DLFCN` modules.
357
.. versionadded:: 2.2
360
.. function:: getfilesystemencoding()
362
Return the name of the encoding used to convert Unicode filenames into system
363
file names, or ``None`` if the system default encoding is used. The result value
364
depends on the operating system:
366
* On Windows 9x, the encoding is "mbcs".
368
* On Mac OS X, the encoding is "utf-8".
370
* On Unix, the encoding is the user's preference according to the result of
371
nl_langinfo(CODESET), or :const:`None` if the ``nl_langinfo(CODESET)`` failed.
373
* On Windows NT+, file names are Unicode natively, so no conversion is
374
performed. :func:`getfilesystemencoding` still returns ``'mbcs'``, as this is
375
the encoding that applications should use when they explicitly want to convert
376
Unicode strings to byte strings that are equivalent when used as file names.
378
.. versionadded:: 2.3
381
.. function:: getrefcount(object)
383
Return the reference count of the *object*. The count returned is generally one
384
higher than you might expect, because it includes the (temporary) reference as
385
an argument to :func:`getrefcount`.
388
.. function:: getrecursionlimit()
390
Return the current value of the recursion limit, the maximum depth of the Python
391
interpreter stack. This limit prevents infinite recursion from causing an
392
overflow of the C stack and crashing Python. It can be set by
393
:func:`setrecursionlimit`.
396
.. function:: getsizeof(object[, default])
398
Return the size of an object in bytes. The object can be any type of
399
object. All built-in objects will return correct results, but this
400
does not have to hold true for third-party extensions as it is implementation
403
The *default* argument allows to define a value which will be returned
404
if the object type does not provide means to retrieve the size and would
407
func:`getsizeof` calls the object's __sizeof__ method and adds an additional
408
garbage collector overhead if the object is managed by the garbage collector.
410
.. versionadded:: 2.6
413
.. function:: _getframe([depth])
415
Return a frame object from the call stack. If optional integer *depth* is
416
given, return the frame object that many calls below the top of the stack. If
417
that is deeper than the call stack, :exc:`ValueError` is raised. The default
418
for *depth* is zero, returning the frame at the top of the call stack.
420
This function should be used for internal and specialized purposes only.
423
.. function:: getprofile()
426
single: profile function
429
Get the profiler function as set by :func:`setprofile`.
431
.. versionadded:: 2.6
434
.. function:: gettrace()
437
single: trace function
440
Get the trace function as set by :func:`settrace`.
444
The :func:`gettrace` function is intended only for implementing debuggers,
445
profilers, coverage tools and the like. Its behavior is part of the
446
implementation platform, rather than part of the language definition,
447
and thus may not be available in all Python implementations.
449
.. versionadded:: 2.6
452
.. function:: getwindowsversion()
454
Return a tuple containing five components, describing the Windows version
455
currently running. The elements are *major*, *minor*, *build*, *platform*, and
456
*text*. *text* contains a string while all other values are integers.
458
*platform* may be one of the following values:
460
+-----------------------------------------+-------------------------+
461
| Constant | Platform |
462
+=========================================+=========================+
463
| :const:`0 (VER_PLATFORM_WIN32s)` | Win32s on Windows 3.1 |
464
+-----------------------------------------+-------------------------+
465
| :const:`1 (VER_PLATFORM_WIN32_WINDOWS)` | Windows 95/98/ME |
466
+-----------------------------------------+-------------------------+
467
| :const:`2 (VER_PLATFORM_WIN32_NT)` | Windows NT/2000/XP/x64 |
468
+-----------------------------------------+-------------------------+
469
| :const:`3 (VER_PLATFORM_WIN32_CE)` | Windows CE |
470
+-----------------------------------------+-------------------------+
472
This function wraps the Win32 :cfunc:`GetVersionEx` function; see the Microsoft
473
documentation for more information about these fields.
475
Availability: Windows.
477
.. versionadded:: 2.3
482
The version number encoded as a single integer. This is guaranteed to increase
483
with each version, including proper support for non-production releases. For
484
example, to test that the Python interpreter is at least version 1.5.2, use::
486
if sys.hexversion >= 0x010502F0:
487
# use some advanced feature
490
# use an alternative implementation or warn the user
493
This is called ``hexversion`` since it only really looks meaningful when viewed
494
as the result of passing it to the built-in :func:`hex` function. The
495
``version_info`` value may be used for a more human-friendly encoding of the
498
.. versionadded:: 1.5.2
505
These three variables are not always defined; they are set when an exception is
506
not handled and the interpreter prints an error message and a stack traceback.
507
Their intended use is to allow an interactive user to import a debugger module
508
and engage in post-mortem debugging without having to re-execute the command
509
that caused the error. (Typical use is ``import pdb; pdb.pm()`` to enter the
510
post-mortem debugger; see chapter :ref:`debugger` for
513
The meaning of the variables is the same as that of the return values from
514
:func:`exc_info` above. (Since there is only one interactive thread,
515
thread-safety is not a concern for these variables, unlike for ``exc_type``
521
The largest positive integer supported by Python's regular integer type. This
522
is at least 2\*\*31-1. The largest negative integer is ``-maxint-1`` --- the
523
asymmetry results from the use of 2's complement binary arithmetic.
527
The largest positive integer supported by the platform's Py_ssize_t type,
528
and thus the maximum size lists, strings, dicts, and many other containers
533
An integer giving the largest supported code point for a Unicode character. The
534
value of this depends on the configuration option that specifies whether Unicode
535
characters are stored as UCS-2 or UCS-4.
540
.. index:: builtin: reload
542
This is a dictionary that maps module names to modules which have already been
543
loaded. This can be manipulated to force reloading of modules and other tricks.
544
Note that removing a module from this dictionary is *not* the same as calling
545
:func:`reload` on the corresponding module object.
550
.. index:: triple: module; search; path
552
A list of strings that specifies the search path for modules. Initialized from
553
the environment variable :envvar:`PYTHONPATH`, plus an installation-dependent
556
As initialized upon program startup, the first item of this list, ``path[0]``,
557
is the directory containing the script that was used to invoke the Python
558
interpreter. If the script directory is not available (e.g. if the interpreter
559
is invoked interactively or if the script is read from standard input),
560
``path[0]`` is the empty string, which directs Python to search modules in the
561
current directory first. Notice that the script directory is inserted *before*
562
the entries inserted as a result of :envvar:`PYTHONPATH`.
564
A program is free to modify this list for its own purposes.
566
.. versionchanged:: 2.3
567
Unicode strings are no longer ignored.
572
This string contains a platform identifier that can be used to append
573
platform-specific components to :data:`sys.path`, for instance.
575
For Unix systems, this is the lowercased OS name as returned by ``uname -s``
576
with the first part of the version as returned by ``uname -r`` appended,
577
e.g. ``'sunos5'`` or ``'linux2'``, *at the time when Python was built*.
578
For other systems, the values are:
580
================ ===========================
581
System :data:`platform` value
582
================ ===========================
584
Windows/Cygwin ``'cygwin'``
585
Mac OS X ``'darwin'``
588
OS/2 EMX ``'os2emx'``
591
================ ===========================
596
A string giving the site-specific directory prefix where the platform
597
independent Python files are installed; by default, this is the string
598
``'/usr/local'``. This can be set at build time with the :option:`--prefix`
599
argument to the :program:`configure` script. The main collection of Python
600
library modules is installed in the directory ``prefix + '/lib/pythonversion'``
601
while the platform independent header files (all except :file:`pyconfig.h`) are
602
stored in ``prefix + '/include/pythonversion'``, where *version* is equal to
610
single: interpreter prompts
611
single: prompts, interpreter
613
Strings specifying the primary and secondary prompt of the interpreter. These
614
are only defined if the interpreter is in interactive mode. Their initial
615
values in this case are ``'>>> '`` and ``'... '``. If a non-string object is
616
assigned to either variable, its :func:`str` is re-evaluated each time the
617
interpreter prepares to read a new interactive command; this can be used to
618
implement a dynamic prompt.
621
.. data:: py3kwarning
623
Bool containing the status of the Python 3.0 warning flag. It's ``True``
624
when Python is started with the -3 option.
626
.. versionadded:: 2.6
629
.. data:: dont_write_bytecode
631
If this is true, Python won't try to write ``.pyc`` or ``.pyo`` files on the
632
import of source modules. This value is initially set to ``True`` or ``False``
633
depending on the ``-B`` command line option and the ``PYTHONDONTWRITEBYTECODE``
634
environment variable, but you can set it yourself to control bytecode file
637
.. versionadded:: 2.6
640
.. function:: setcheckinterval(interval)
642
Set the interpreter's "check interval". This integer value determines how often
643
the interpreter checks for periodic things such as thread switches and signal
644
handlers. The default is ``100``, meaning the check is performed every 100
645
Python virtual instructions. Setting it to a larger value may increase
646
performance for programs using threads. Setting it to a value ``<=`` 0 checks
647
every virtual instruction, maximizing responsiveness as well as overhead.
650
.. function:: setdefaultencoding(name)
652
Set the current default string encoding used by the Unicode implementation. If
653
*name* does not match any available encoding, :exc:`LookupError` is raised.
654
This function is only intended to be used by the :mod:`site` module
655
implementation and, where needed, by :mod:`sitecustomize`. Once used by the
656
:mod:`site` module, it is removed from the :mod:`sys` module's namespace.
658
.. Note that :mod:`site` is not imported if the :option:`-S` option is passed
659
to the interpreter, in which case this function will remain available.
661
.. versionadded:: 2.0
664
.. function:: setdlopenflags(n)
666
Set the flags used by the interpreter for :cfunc:`dlopen` calls, such as when
667
the interpreter loads extension modules. Among other things, this will enable a
668
lazy resolving of symbols when importing a module, if called as
669
``sys.setdlopenflags(0)``. To share symbols across extension modules, call as
670
``sys.setdlopenflags(dl.RTLD_NOW | dl.RTLD_GLOBAL)``. Symbolic names for the
671
flag modules can be either found in the :mod:`dl` module, or in the :mod:`DLFCN`
672
module. If :mod:`DLFCN` is not available, it can be generated from
673
:file:`/usr/include/dlfcn.h` using the :program:`h2py` script. Availability:
676
.. versionadded:: 2.2
679
.. function:: setprofile(profilefunc)
682
single: profile function
685
Set the system's profile function, which allows you to implement a Python source
686
code profiler in Python. See chapter :ref:`profile` for more information on the
687
Python profiler. The system's profile function is called similarly to the
688
system's trace function (see :func:`settrace`), but it isn't called for each
689
executed line of code (only on call and return, but the return event is reported
690
even when an exception has been set). The function is thread-specific, but
691
there is no way for the profiler to know about context switches between threads,
692
so it does not make sense to use this in the presence of multiple threads. Also,
693
its return value is not used, so it can simply return ``None``.
696
.. function:: setrecursionlimit(limit)
698
Set the maximum depth of the Python interpreter stack to *limit*. This limit
699
prevents infinite recursion from causing an overflow of the C stack and crashing
702
The highest possible limit is platform-dependent. A user may need to set the
703
limit higher when she has a program that requires deep recursion and a platform
704
that supports a higher limit. This should be done with care, because a too-high
705
limit can lead to a crash.
708
.. function:: settrace(tracefunc)
711
single: trace function
714
Set the system's trace function, which allows you to implement a Python
715
source code debugger in Python. See section :ref:`debugger-hooks` in the
716
chapter on the Python debugger. The function is thread-specific; for a
717
debugger to support multiple threads, it must be registered using
718
:func:`settrace` for each thread being debugged.
722
The :func:`settrace` function is intended only for implementing debuggers,
723
profilers, coverage tools and the like. Its behavior is part of the
724
implementation platform, rather than part of the language definition, and thus
725
may not be available in all Python implementations.
728
.. function:: settscdump(on_flag)
730
Activate dumping of VM measurements using the Pentium timestamp counter, if
731
*on_flag* is true. Deactivate these dumps if *on_flag* is off. The function is
732
available only if Python was compiled with :option:`--with-tsc`. To understand
733
the output of this dump, read :file:`Python/ceval.c` in the Python sources.
735
.. versionadded:: 2.4
746
File objects corresponding to the interpreter's standard input, output and error
747
streams. ``stdin`` is used for all interpreter input except for scripts but
748
including calls to :func:`input` and :func:`raw_input`. ``stdout`` is used for
749
the output of :keyword:`print` and :term:`expression` statements and for the
750
prompts of :func:`input` and :func:`raw_input`. The interpreter's own prompts
751
and (almost all of) its error messages go to ``stderr``. ``stdout`` and
752
``stderr`` needn't be built-in file objects: any object is acceptable as long
753
as it has a :meth:`write` method that takes a string argument. (Changing these
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objects doesn't affect the standard I/O streams of processes executed by
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:func:`os.popen`, :func:`os.system` or the :func:`exec\*` family of functions in
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the :mod:`os` module.)
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These objects contain the original values of ``stdin``, ``stderr`` and
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``stdout`` at the start of the program. They are used during finalization, and
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could be useful to restore the actual files to known working file objects in
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case they have been overwritten with a broken object.
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.. data:: tracebacklimit
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When this variable is set to an integer value, it determines the maximum number
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of levels of traceback information printed when an unhandled exception occurs.
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The default is ``1000``. When set to ``0`` or less, all traceback information
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is suppressed and only the exception type and value are printed.
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A string containing the version number of the Python interpreter plus additional
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information on the build number and compiler used. It has a value of the form
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``'version (#build_number, build_date, build_time) [compiler]'``. The first
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three characters are used to identify the version in the installation
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directories (where appropriate on each platform). An example::
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'1.5.2 (#0 Apr 13 1999, 10:51:12) [MSC 32 bit (Intel)]'
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.. data:: api_version
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The C API version for this interpreter. Programmers may find this useful when
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debugging version conflicts between Python and extension modules.
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.. versionadded:: 2.3
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.. data:: version_info
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A tuple containing the five components of the version number: *major*, *minor*,
801
*micro*, *releaselevel*, and *serial*. All values except *releaselevel* are
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integers; the release level is ``'alpha'``, ``'beta'``, ``'candidate'``, or
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``'final'``. The ``version_info`` value corresponding to the Python version 2.0
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is ``(2, 0, 0, 'final', 0)``.
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.. versionadded:: 2.0
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.. data:: warnoptions
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This is an implementation detail of the warnings framework; do not modify this
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value. Refer to the :mod:`warnings` module for more information on the warnings
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The version number used to form registry keys on Windows platforms. This is
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stored as string resource 1000 in the Python DLL. The value is normally the
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first three characters of :const:`version`. It is provided in the :mod:`sys`
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module for informational purposes; modifying this value has no effect on the
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registry keys used by Python. Availability: Windows.
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This describes how to use .pth files to extend ``sys.path``.
added
removed
Doc/library/sys.rst
