cpython/Doc/library/sys.rst

746 lines
32 KiB
ReStructuredText
Raw Normal View History

2007-08-15 11:28:22 -03:00
: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.
.. 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``.
.. 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.)
.. data:: copyright
A string containing the copyright pertaining to the Python interpreter.
Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552-60567 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60553 | neal.norwitz | 2008-02-03 17:53:09 +0100 (Sun, 03 Feb 2008) | 1 line Ignore leaky warnings from test_asynchat ........ r60555 | christian.heimes | 2008-02-03 20:51:13 +0100 (Sun, 03 Feb 2008) | 1 line Another int -> pid_t case ........ r60560 | amaury.forgeotdarc | 2008-02-03 23:51:43 +0100 (Sun, 03 Feb 2008) | 6 lines Ensure that PySet_Add() operates on a newly created frozenset, like PyTuple_SetItem does. Add PyFrozenSet_Check(), which was not needed before; The list of Py*Set_Check* macros seems to be complete now. Add missing NEWS entries about all this. ........ r60563 | amaury.forgeotdarc | 2008-02-04 00:14:32 +0100 (Mon, 04 Feb 2008) | 2 lines Nasty typo in setobject.h ........ r60564 | amaury.forgeotdarc | 2008-02-04 00:15:32 +0100 (Mon, 04 Feb 2008) | 3 lines Correct test_mailbox on win32: since the test sets a custom 'colon' attribute to the main mailbox, copy it to secondary mailbox instances. ........ r60565 | amaury.forgeotdarc | 2008-02-04 00:57:24 +0100 (Mon, 04 Feb 2008) | 2 lines Let test_socketserver pass on win32, which does not have AF_UNIX sockets. ........ r60566 | jeffrey.yasskin | 2008-02-04 02:04:35 +0100 (Mon, 04 Feb 2008) | 2 lines Make int() and long() fall back to __trunc__(). See issue 2002. ........ r60567 | christian.heimes | 2008-02-04 19:00:12 +0100 (Mon, 04 Feb 2008) | 3 lines Patch #1953 I implemented the function sys._compact_freelists() and C API functions PyInt_/PyFloat_CompactFreeList() to compact the pre-allocated blocks of ints and floats. They allow the user to reduce the memory usage of a Python process that deals with lots of numbers. The patch also renames sys._cleartypecache to sys._clear_type_cache ........
2008-02-04 14:48:49 -04:00
.. function:: _compact_freelists()
Merged revisions 60364-60378 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60364 | neal.norwitz | 2008-01-27 19:09:48 +0100 (Sun, 27 Jan 2008) | 4 lines Update the comment and remove the close. If we close we can't flush anymore. We might still need to close after the for loop if flushing 6! times still doesn't cause the signal/exception. ........ r60365 | georg.brandl | 2008-01-27 19:14:43 +0100 (Sun, 27 Jan 2008) | 2 lines Remove effectless expression statement. ........ r60367 | neal.norwitz | 2008-01-27 19:19:04 +0100 (Sun, 27 Jan 2008) | 1 line Try to handle socket.errors properly in is_unavailable ........ r60370 | christian.heimes | 2008-01-27 20:01:45 +0100 (Sun, 27 Jan 2008) | 1 line Change isbasestring function as discussed on the cvs list a while ago ........ r60372 | neal.norwitz | 2008-01-27 21:03:13 +0100 (Sun, 27 Jan 2008) | 3 lines socket.error doesn't have a headers attribute like ProtocolError. Handle that situation where we catch socket.errors. ........ r60375 | georg.brandl | 2008-01-27 21:25:12 +0100 (Sun, 27 Jan 2008) | 2 lines Add refcounting extension to build config. ........ r60377 | jeffrey.yasskin | 2008-01-28 00:08:46 +0100 (Mon, 28 Jan 2008) | 6 lines Moved Rational._binary_float_to_ratio() to float.as_integer_ratio() because it's useful outside of rational numbers. This is my first C code that had to do anything significant. Please be more careful when looking over it. ........ r60378 | christian.heimes | 2008-01-28 00:34:59 +0100 (Mon, 28 Jan 2008) | 1 line Added clear cache methods to clear the internal type lookup cache for ref leak test runs. ........
2008-01-27 19:50:43 -04:00
Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552-60567 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60553 | neal.norwitz | 2008-02-03 17:53:09 +0100 (Sun, 03 Feb 2008) | 1 line Ignore leaky warnings from test_asynchat ........ r60555 | christian.heimes | 2008-02-03 20:51:13 +0100 (Sun, 03 Feb 2008) | 1 line Another int -> pid_t case ........ r60560 | amaury.forgeotdarc | 2008-02-03 23:51:43 +0100 (Sun, 03 Feb 2008) | 6 lines Ensure that PySet_Add() operates on a newly created frozenset, like PyTuple_SetItem does. Add PyFrozenSet_Check(), which was not needed before; The list of Py*Set_Check* macros seems to be complete now. Add missing NEWS entries about all this. ........ r60563 | amaury.forgeotdarc | 2008-02-04 00:14:32 +0100 (Mon, 04 Feb 2008) | 2 lines Nasty typo in setobject.h ........ r60564 | amaury.forgeotdarc | 2008-02-04 00:15:32 +0100 (Mon, 04 Feb 2008) | 3 lines Correct test_mailbox on win32: since the test sets a custom 'colon' attribute to the main mailbox, copy it to secondary mailbox instances. ........ r60565 | amaury.forgeotdarc | 2008-02-04 00:57:24 +0100 (Mon, 04 Feb 2008) | 2 lines Let test_socketserver pass on win32, which does not have AF_UNIX sockets. ........ r60566 | jeffrey.yasskin | 2008-02-04 02:04:35 +0100 (Mon, 04 Feb 2008) | 2 lines Make int() and long() fall back to __trunc__(). See issue 2002. ........ r60567 | christian.heimes | 2008-02-04 19:00:12 +0100 (Mon, 04 Feb 2008) | 3 lines Patch #1953 I implemented the function sys._compact_freelists() and C API functions PyInt_/PyFloat_CompactFreeList() to compact the pre-allocated blocks of ints and floats. They allow the user to reduce the memory usage of a Python process that deals with lots of numbers. The patch also renames sys._cleartypecache to sys._clear_type_cache ........
2008-02-04 14:48:49 -04:00
Compact the free list of floats by deallocating unused blocks.
It can reduce the memory usage of the Python process several tenth of
thousands of integers or floats have been allocated at once.
The return value is a tuple of tuples each containing three elements,
amount of used objects, total block count before the blocks are deallocated
and amount of freed blocks.
This function should be used for specialized purposes only.
.. versionadded:: 2.6
.. 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.
Merged revisions 60364-60378 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60364 | neal.norwitz | 2008-01-27 19:09:48 +0100 (Sun, 27 Jan 2008) | 4 lines Update the comment and remove the close. If we close we can't flush anymore. We might still need to close after the for loop if flushing 6! times still doesn't cause the signal/exception. ........ r60365 | georg.brandl | 2008-01-27 19:14:43 +0100 (Sun, 27 Jan 2008) | 2 lines Remove effectless expression statement. ........ r60367 | neal.norwitz | 2008-01-27 19:19:04 +0100 (Sun, 27 Jan 2008) | 1 line Try to handle socket.errors properly in is_unavailable ........ r60370 | christian.heimes | 2008-01-27 20:01:45 +0100 (Sun, 27 Jan 2008) | 1 line Change isbasestring function as discussed on the cvs list a while ago ........ r60372 | neal.norwitz | 2008-01-27 21:03:13 +0100 (Sun, 27 Jan 2008) | 3 lines socket.error doesn't have a headers attribute like ProtocolError. Handle that situation where we catch socket.errors. ........ r60375 | georg.brandl | 2008-01-27 21:25:12 +0100 (Sun, 27 Jan 2008) | 2 lines Add refcounting extension to build config. ........ r60377 | jeffrey.yasskin | 2008-01-28 00:08:46 +0100 (Mon, 28 Jan 2008) | 6 lines Moved Rational._binary_float_to_ratio() to float.as_integer_ratio() because it's useful outside of rational numbers. This is my first C code that had to do anything significant. Please be more careful when looking over it. ........ r60378 | christian.heimes | 2008-01-28 00:34:59 +0100 (Mon, 28 Jan 2008) | 1 line Added clear cache methods to clear the internal type lookup cache for ref leak test runs. ........
2008-01-27 19:50:43 -04:00
.. versionadded:: 2.6
2007-08-15 11:28:22 -03:00
.. 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.
.. 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 ``builtins._``.
2007-08-15 11:28:22 -03:00
Merged revisions 59259-59274 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines Issue #1531: Read fileobj from the current offset, do not seek to the start. (will backport to 2.5) ........ r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines Document PyEval_* functions from ceval.c. Credits to Michael Sloan from GHOP. ........ r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines Add a few refcount data entries. ........ r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines Add test suite for cmd module. Written by Michael Schneider for GHOP. ........ r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines Add examples to the ElementTree documentation. Written by h4wk.cz for GHOP. ........ r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines Add "Using Python on Windows" document, by Robert Lehmann. Written for GHOP. ........ r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines Add example to mmap docs. Written for GHOP by Rafal Rawicki. ........ r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines Convert bdb.rst line endings to Unix style. ........ r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines Add more entries to the glossary. Written by Jeff Wheeler for GHOP. ........
2007-12-02 11:22:16 -04:00
``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``.
2007-08-15 11:28:22 -03:00
.. 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.
.. 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.
.. 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 :option:`--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 ``exec_prefix +
'/lib/pythonversion/config'``, and shared library modules are installed in
``exec_prefix + '/lib/pythonversion/lib-dynload'``, where *version* is equal to
``version[:3]``.
.. data:: executable
A string giving the name of the executable binary for the Python interpreter, on
systems where this makes sense.
.. 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
``sys.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.
Merged revisions 59933-59951 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59935 | raymond.hettinger | 2008-01-13 07:15:15 +0100 (Sun, 13 Jan 2008) | 1 line Named tuple is a concept, not a specific type. ........ r59936 | raymond.hettinger | 2008-01-13 07:18:07 +0100 (Sun, 13 Jan 2008) | 1 line Fix spelling. ........ r59937 | georg.brandl | 2008-01-13 10:36:18 +0100 (Sun, 13 Jan 2008) | 2 lines Clarify the effect of text mode. ........ r59938 | thomas.heller | 2008-01-13 12:19:43 +0100 (Sun, 13 Jan 2008) | 1 line Make Modules/socketobject.c compile for Windows again. ........ r59939 | ka-ping.yee | 2008-01-13 12:25:13 +0100 (Sun, 13 Jan 2008) | 9 lines Check in the patch proposed by Ben Hayden (benjhayden) for issue #1550: help('modules') broken by several 3rd party libraries. Tested with Python build: trunk:54235:59936M -- the reported error occurs with Django installed (or with any __init__.py present on the path that raises an exception), and such errors indeed go away when this change is applied. ........ r59940 | georg.brandl | 2008-01-13 16:04:05 +0100 (Sun, 13 Jan 2008) | 2 lines Back out r59931 - test_ctypes fails with it. ........ r59943 | amaury.forgeotdarc | 2008-01-14 01:22:44 +0100 (Mon, 14 Jan 2008) | 6 lines As discussed in issue 1700288: ctypes takes some liberties when creating python types: it modifies the types' __dict__ directly, bypassing all the machinery of type objects which deal with special methods. And this broke recent optimisations of method lookup. Now we try to modify the type with more "official" functions. ........ r59944 | amaury.forgeotdarc | 2008-01-14 01:29:41 +0100 (Mon, 14 Jan 2008) | 5 lines Re-apply patch #1700288 (first applied in r59931, rolled back in r59940) now that ctypes uses a more supported method to create types: Method cache optimization, by Armin Rigo, ported to 2.6 by Kevin Jacobs. ........ r59946 | amaury.forgeotdarc | 2008-01-14 02:07:27 +0100 (Mon, 14 Jan 2008) | 4 lines ?Why did my tests not notice this before? Slots inheritance is very different from OO inheritance. This code lead to infinite recursion on classes derived from StructType. ........ r59947 | christian.heimes | 2008-01-14 04:33:52 +0100 (Mon, 14 Jan 2008) | 1 line Added new an better structseq representation. E.g. repr(time.gmtime(0)) now returns 'time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)' instead of '(1970, 1, 1, 0, 0, 0, 3, 1, 0)'. The feature is part of #1816: sys.flags ........ r59948 | christian.heimes | 2008-01-14 04:35:38 +0100 (Mon, 14 Jan 2008) | 1 line I missed the most important file ........ r59949 | christian.heimes | 2008-01-14 04:42:48 +0100 (Mon, 14 Jan 2008) | 1 line Applied patch #1816: sys.flags patch ........ r59950 | christian.heimes | 2008-01-14 05:13:37 +0100 (Mon, 14 Jan 2008) | 2 lines Now that I've learnt about structseq objects I felt like converting sys.float_info to a structseq. It's readonly and help(sys.float_info) explains the attributes nicely. ........ r59951 | christian.heimes | 2008-01-14 07:06:19 +0100 (Mon, 14 Jan 2008) | 1 line Added more comments to the new structseq repr code and implemented several of Neal's suggestions. ........
2008-01-14 14:49:24 -04:00
.. data:: flags
The struct sequence *flags* exposes the status of command line flags. The
attributes are read only.
+------------------------------+------------------------------------------+
| attribute | flag |
+==============================+==========================================+
| :const:`debug` | -d |
+------------------------------+------------------------------------------+
| :const:`py3k_warning` | -3 |
+------------------------------+------------------------------------------+
| :const:`division_warning` | -Q |
+------------------------------+------------------------------------------+
| :const:`division_new` | -Qnew |
+------------------------------+------------------------------------------+
| :const:`inspect` | -i |
+------------------------------+------------------------------------------+
| :const:`interactive` | -i |
+------------------------------+------------------------------------------+
| :const:`optimize` | -O or -OO |
+------------------------------+------------------------------------------+
| :const:`dont_write_bytecode` | -B |
+------------------------------+------------------------------------------+
| :const:`no_site` | -S |
+------------------------------+------------------------------------------+
Merged revisions 59952-59984 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59952 | thomas.heller | 2008-01-14 02:35:28 -0800 (Mon, 14 Jan 2008) | 1 line Issue 1821: configure libffi for amd64 on FreeeBSD. ........ r59953 | andrew.kuchling | 2008-01-14 06:48:43 -0800 (Mon, 14 Jan 2008) | 1 line Update description of float_info ........ r59959 | raymond.hettinger | 2008-01-14 14:58:05 -0800 (Mon, 14 Jan 2008) | 1 line Fix 1698398: Zipfile.printdir() crashed because the format string expected a tuple object of length six instead of a time.struct_time object. ........ r59961 | andrew.kuchling | 2008-01-14 17:29:16 -0800 (Mon, 14 Jan 2008) | 1 line Typo fixes ........ r59962 | andrew.kuchling | 2008-01-14 17:29:44 -0800 (Mon, 14 Jan 2008) | 1 line Markup fix ........ r59963 | andrew.kuchling | 2008-01-14 17:47:32 -0800 (Mon, 14 Jan 2008) | 1 line Add many items ........ r59964 | andrew.kuchling | 2008-01-14 17:55:32 -0800 (Mon, 14 Jan 2008) | 1 line Repair unfinished sentence ........ r59967 | raymond.hettinger | 2008-01-14 19:02:37 -0800 (Mon, 14 Jan 2008) | 5 lines Issue 1820: structseq objects did not work with the % formatting operator or isinstance(t, tuple). Orignal patch (without tests) by Leif Walsh. ........ r59968 | raymond.hettinger | 2008-01-14 19:07:42 -0800 (Mon, 14 Jan 2008) | 1 line Tighten the definition of a named tuple. ........ r59969 | skip.montanaro | 2008-01-14 19:40:20 -0800 (Mon, 14 Jan 2008) | 3 lines Better (?) text describing the lack of guarantees provided by qsize(), empty() and full(). ........ r59970 | raymond.hettinger | 2008-01-14 21:39:59 -0800 (Mon, 14 Jan 2008) | 1 line Temporarily revert 59967 until GC can be added. ........ r59971 | raymond.hettinger | 2008-01-14 21:46:43 -0800 (Mon, 14 Jan 2008) | 1 line Small grammar nit ........ r59972 | georg.brandl | 2008-01-14 22:55:56 -0800 (Mon, 14 Jan 2008) | 2 lines Typo. ........ r59973 | georg.brandl | 2008-01-14 22:58:15 -0800 (Mon, 14 Jan 2008) | 2 lines Remove duplicate entry. ........ r59974 | jeffrey.yasskin | 2008-01-14 23:46:24 -0800 (Mon, 14 Jan 2008) | 12 lines Add rational.Rational as an implementation of numbers.Rational with infinite precision. This has been discussed at http://bugs.python.org/issue1682. It's useful primarily for teaching, but it also demonstrates how to implement a member of the numeric tower, including fallbacks for mixed-mode arithmetic. I expect to write a couple more patches in this area: * Rational.from_decimal() * Rational.trim/approximate() (maybe with different names) * Maybe remove the parentheses from Rational.__str__() * Maybe rename one of the Rational classes * Maybe make Rational('3/2') work. ........ r59978 | andrew.kuchling | 2008-01-15 06:38:05 -0800 (Tue, 15 Jan 2008) | 8 lines Restore description of sys.dont_write_bytecode. The duplication is intentional -- this paragraph is in a section describing additions to the sys module, and there's a later section that mentions the switch. I think most people scan the what's-new and don't read it in detail, so a bit of duplication is OK. ........ r59984 | guido.van.rossum | 2008-01-15 09:59:29 -0800 (Tue, 15 Jan 2008) | 3 lines Issue #1786 (by myself): pdb should use its own stdin/stdout around an exec call and when creating a recursive instance. ........
2008-01-15 17:44:53 -04:00
| :const:`ignore_environment` | -E |
Merged revisions 59933-59951 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59935 | raymond.hettinger | 2008-01-13 07:15:15 +0100 (Sun, 13 Jan 2008) | 1 line Named tuple is a concept, not a specific type. ........ r59936 | raymond.hettinger | 2008-01-13 07:18:07 +0100 (Sun, 13 Jan 2008) | 1 line Fix spelling. ........ r59937 | georg.brandl | 2008-01-13 10:36:18 +0100 (Sun, 13 Jan 2008) | 2 lines Clarify the effect of text mode. ........ r59938 | thomas.heller | 2008-01-13 12:19:43 +0100 (Sun, 13 Jan 2008) | 1 line Make Modules/socketobject.c compile for Windows again. ........ r59939 | ka-ping.yee | 2008-01-13 12:25:13 +0100 (Sun, 13 Jan 2008) | 9 lines Check in the patch proposed by Ben Hayden (benjhayden) for issue #1550: help('modules') broken by several 3rd party libraries. Tested with Python build: trunk:54235:59936M -- the reported error occurs with Django installed (or with any __init__.py present on the path that raises an exception), and such errors indeed go away when this change is applied. ........ r59940 | georg.brandl | 2008-01-13 16:04:05 +0100 (Sun, 13 Jan 2008) | 2 lines Back out r59931 - test_ctypes fails with it. ........ r59943 | amaury.forgeotdarc | 2008-01-14 01:22:44 +0100 (Mon, 14 Jan 2008) | 6 lines As discussed in issue 1700288: ctypes takes some liberties when creating python types: it modifies the types' __dict__ directly, bypassing all the machinery of type objects which deal with special methods. And this broke recent optimisations of method lookup. Now we try to modify the type with more "official" functions. ........ r59944 | amaury.forgeotdarc | 2008-01-14 01:29:41 +0100 (Mon, 14 Jan 2008) | 5 lines Re-apply patch #1700288 (first applied in r59931, rolled back in r59940) now that ctypes uses a more supported method to create types: Method cache optimization, by Armin Rigo, ported to 2.6 by Kevin Jacobs. ........ r59946 | amaury.forgeotdarc | 2008-01-14 02:07:27 +0100 (Mon, 14 Jan 2008) | 4 lines ?Why did my tests not notice this before? Slots inheritance is very different from OO inheritance. This code lead to infinite recursion on classes derived from StructType. ........ r59947 | christian.heimes | 2008-01-14 04:33:52 +0100 (Mon, 14 Jan 2008) | 1 line Added new an better structseq representation. E.g. repr(time.gmtime(0)) now returns 'time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)' instead of '(1970, 1, 1, 0, 0, 0, 3, 1, 0)'. The feature is part of #1816: sys.flags ........ r59948 | christian.heimes | 2008-01-14 04:35:38 +0100 (Mon, 14 Jan 2008) | 1 line I missed the most important file ........ r59949 | christian.heimes | 2008-01-14 04:42:48 +0100 (Mon, 14 Jan 2008) | 1 line Applied patch #1816: sys.flags patch ........ r59950 | christian.heimes | 2008-01-14 05:13:37 +0100 (Mon, 14 Jan 2008) | 2 lines Now that I've learnt about structseq objects I felt like converting sys.float_info to a structseq. It's readonly and help(sys.float_info) explains the attributes nicely. ........ r59951 | christian.heimes | 2008-01-14 07:06:19 +0100 (Mon, 14 Jan 2008) | 1 line Added more comments to the new structseq repr code and implemented several of Neal's suggestions. ........
2008-01-14 14:49:24 -04:00
+------------------------------+------------------------------------------+
| :const:`tabcheck` | -t or -tt |
+------------------------------+------------------------------------------+
| :const:`verbose` | -v |
+------------------------------+------------------------------------------+
| :const:`unicode` | -U |
+------------------------------+------------------------------------------+
.. versionadded:: 2.6
.. data:: float_info
Merged revisions 59933-59951 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59935 | raymond.hettinger | 2008-01-13 07:15:15 +0100 (Sun, 13 Jan 2008) | 1 line Named tuple is a concept, not a specific type. ........ r59936 | raymond.hettinger | 2008-01-13 07:18:07 +0100 (Sun, 13 Jan 2008) | 1 line Fix spelling. ........ r59937 | georg.brandl | 2008-01-13 10:36:18 +0100 (Sun, 13 Jan 2008) | 2 lines Clarify the effect of text mode. ........ r59938 | thomas.heller | 2008-01-13 12:19:43 +0100 (Sun, 13 Jan 2008) | 1 line Make Modules/socketobject.c compile for Windows again. ........ r59939 | ka-ping.yee | 2008-01-13 12:25:13 +0100 (Sun, 13 Jan 2008) | 9 lines Check in the patch proposed by Ben Hayden (benjhayden) for issue #1550: help('modules') broken by several 3rd party libraries. Tested with Python build: trunk:54235:59936M -- the reported error occurs with Django installed (or with any __init__.py present on the path that raises an exception), and such errors indeed go away when this change is applied. ........ r59940 | georg.brandl | 2008-01-13 16:04:05 +0100 (Sun, 13 Jan 2008) | 2 lines Back out r59931 - test_ctypes fails with it. ........ r59943 | amaury.forgeotdarc | 2008-01-14 01:22:44 +0100 (Mon, 14 Jan 2008) | 6 lines As discussed in issue 1700288: ctypes takes some liberties when creating python types: it modifies the types' __dict__ directly, bypassing all the machinery of type objects which deal with special methods. And this broke recent optimisations of method lookup. Now we try to modify the type with more "official" functions. ........ r59944 | amaury.forgeotdarc | 2008-01-14 01:29:41 +0100 (Mon, 14 Jan 2008) | 5 lines Re-apply patch #1700288 (first applied in r59931, rolled back in r59940) now that ctypes uses a more supported method to create types: Method cache optimization, by Armin Rigo, ported to 2.6 by Kevin Jacobs. ........ r59946 | amaury.forgeotdarc | 2008-01-14 02:07:27 +0100 (Mon, 14 Jan 2008) | 4 lines ?Why did my tests not notice this before? Slots inheritance is very different from OO inheritance. This code lead to infinite recursion on classes derived from StructType. ........ r59947 | christian.heimes | 2008-01-14 04:33:52 +0100 (Mon, 14 Jan 2008) | 1 line Added new an better structseq representation. E.g. repr(time.gmtime(0)) now returns 'time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)' instead of '(1970, 1, 1, 0, 0, 0, 3, 1, 0)'. The feature is part of #1816: sys.flags ........ r59948 | christian.heimes | 2008-01-14 04:35:38 +0100 (Mon, 14 Jan 2008) | 1 line I missed the most important file ........ r59949 | christian.heimes | 2008-01-14 04:42:48 +0100 (Mon, 14 Jan 2008) | 1 line Applied patch #1816: sys.flags patch ........ r59950 | christian.heimes | 2008-01-14 05:13:37 +0100 (Mon, 14 Jan 2008) | 2 lines Now that I've learnt about structseq objects I felt like converting sys.float_info to a structseq. It's readonly and help(sys.float_info) explains the attributes nicely. ........ r59951 | christian.heimes | 2008-01-14 07:06:19 +0100 (Mon, 14 Jan 2008) | 1 line Added more comments to the new structseq repr code and implemented several of Neal's suggestions. ........
2008-01-14 14:49:24 -04:00
A structseq holding information about the float type. It contains low level
information about the precision and internal representation. Please study
your system's :file:`float.h` for more information.
+---------------------+--------------------------------------------------+
Merged revisions 59933-59951 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59935 | raymond.hettinger | 2008-01-13 07:15:15 +0100 (Sun, 13 Jan 2008) | 1 line Named tuple is a concept, not a specific type. ........ r59936 | raymond.hettinger | 2008-01-13 07:18:07 +0100 (Sun, 13 Jan 2008) | 1 line Fix spelling. ........ r59937 | georg.brandl | 2008-01-13 10:36:18 +0100 (Sun, 13 Jan 2008) | 2 lines Clarify the effect of text mode. ........ r59938 | thomas.heller | 2008-01-13 12:19:43 +0100 (Sun, 13 Jan 2008) | 1 line Make Modules/socketobject.c compile for Windows again. ........ r59939 | ka-ping.yee | 2008-01-13 12:25:13 +0100 (Sun, 13 Jan 2008) | 9 lines Check in the patch proposed by Ben Hayden (benjhayden) for issue #1550: help('modules') broken by several 3rd party libraries. Tested with Python build: trunk:54235:59936M -- the reported error occurs with Django installed (or with any __init__.py present on the path that raises an exception), and such errors indeed go away when this change is applied. ........ r59940 | georg.brandl | 2008-01-13 16:04:05 +0100 (Sun, 13 Jan 2008) | 2 lines Back out r59931 - test_ctypes fails with it. ........ r59943 | amaury.forgeotdarc | 2008-01-14 01:22:44 +0100 (Mon, 14 Jan 2008) | 6 lines As discussed in issue 1700288: ctypes takes some liberties when creating python types: it modifies the types' __dict__ directly, bypassing all the machinery of type objects which deal with special methods. And this broke recent optimisations of method lookup. Now we try to modify the type with more "official" functions. ........ r59944 | amaury.forgeotdarc | 2008-01-14 01:29:41 +0100 (Mon, 14 Jan 2008) | 5 lines Re-apply patch #1700288 (first applied in r59931, rolled back in r59940) now that ctypes uses a more supported method to create types: Method cache optimization, by Armin Rigo, ported to 2.6 by Kevin Jacobs. ........ r59946 | amaury.forgeotdarc | 2008-01-14 02:07:27 +0100 (Mon, 14 Jan 2008) | 4 lines ?Why did my tests not notice this before? Slots inheritance is very different from OO inheritance. This code lead to infinite recursion on classes derived from StructType. ........ r59947 | christian.heimes | 2008-01-14 04:33:52 +0100 (Mon, 14 Jan 2008) | 1 line Added new an better structseq representation. E.g. repr(time.gmtime(0)) now returns 'time.struct_time(tm_year=1970, tm_mon=1, tm_mday=1, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=1, tm_isdst=0)' instead of '(1970, 1, 1, 0, 0, 0, 3, 1, 0)'. The feature is part of #1816: sys.flags ........ r59948 | christian.heimes | 2008-01-14 04:35:38 +0100 (Mon, 14 Jan 2008) | 1 line I missed the most important file ........ r59949 | christian.heimes | 2008-01-14 04:42:48 +0100 (Mon, 14 Jan 2008) | 1 line Applied patch #1816: sys.flags patch ........ r59950 | christian.heimes | 2008-01-14 05:13:37 +0100 (Mon, 14 Jan 2008) | 2 lines Now that I've learnt about structseq objects I felt like converting sys.float_info to a structseq. It's readonly and help(sys.float_info) explains the attributes nicely. ........ r59951 | christian.heimes | 2008-01-14 07:06:19 +0100 (Mon, 14 Jan 2008) | 1 line Added more comments to the new structseq repr code and implemented several of Neal's suggestions. ........
2008-01-14 14:49:24 -04:00
| attribute | explanation |
+=====================+==================================================+
| :const:`epsilon` | Difference between 1 and the next representable |
| | floating point number |
+---------------------+--------------------------------------------------+
| :const:`dig` | digits (see :file:`float.h`) |
+---------------------+--------------------------------------------------+
| :const:`mant_dig` | mantissa digits (see :file:`float.h`) |
+---------------------+--------------------------------------------------+
| :const:`max` | maximum representable finite float |
+---------------------+--------------------------------------------------+
| :const:`max_exp` | maximum int e such that radix**(e-1) is in the |
| | range of finite representable floats |
+---------------------+--------------------------------------------------+
| :const:`max_10_exp` | maximum int e such that 10**e is in the |
| | range of finite representable floats |
+---------------------+--------------------------------------------------+
| :const:`min` | Minimum positive normalizer float |
+---------------------+--------------------------------------------------+
| :const:`min_exp` | minimum int e such that radix**(e-1) is a |
| | normalized float |
+---------------------+--------------------------------------------------+
| :const:`min_10_exp` | minimum int e such that 10**e is a normalized |
| | float |
+---------------------+--------------------------------------------------+
| :const:`radix` | radix of exponent |
+---------------------+--------------------------------------------------+
| :const:`rounds` | addition rounds (see :file:`float.h`) |
+---------------------+--------------------------------------------------+
.. note::
The information in the table is simplified.
2007-08-15 11:28:22 -03:00
.. function:: getcheckinterval()
Return the interpreter's "check interval"; see :func:`setcheckinterval`.
.. function:: getdefaultencoding()
Return the name of the current default string encoding used by the Unicode
implementation.
.. function:: getdlopenflags()
Return the current value of the flags that are used for :cfunc:`dlopen` calls.
The flag constants are defined in the :mod:`dl` and :mod:`DLFCN` modules.
Availability: Unix.
.. 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 Windows 9x, the encoding is "mbcs".
* 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 :const:`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.
.. 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:: _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.
This function should be used for internal and specialized purposes only.
Merged revisions 60124-60142 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60131 | georg.brandl | 2008-01-20 12:13:29 +0100 (Sun, 20 Jan 2008) | 3 lines #1351692: in pprint, always call format() for dict and list items to enable custom formatting of contents via subclassing PrettyPrinter. ........ r60133 | georg.brandl | 2008-01-20 12:43:03 +0100 (Sun, 20 Jan 2008) | 2 lines #1178141: add addinfourl.code to get http status code from urllib. ........ r60134 | georg.brandl | 2008-01-20 13:05:43 +0100 (Sun, 20 Jan 2008) | 4 lines #856047: respect the ``no_proxy`` env var when checking for proxies in urllib and using the other ``_proxy`` env vars. Original patch by Donovan Baarda. ........ r60135 | georg.brandl | 2008-01-20 13:18:17 +0100 (Sun, 20 Jan 2008) | 4 lines #1664522: in urllib, don't read non-existing directories in ftp mode, returning a 0-byte file -- raise an IOError instead. Original patch from Phil Knirsch. ........ r60136 | georg.brandl | 2008-01-20 13:57:47 +0100 (Sun, 20 Jan 2008) | 2 lines #799369: document possible sys.platform values. ........ r60137 | georg.brandl | 2008-01-20 14:08:37 +0100 (Sun, 20 Jan 2008) | 2 lines #652749: document the constants added to the builtins by site.py. ........ r60138 | georg.brandl | 2008-01-20 14:59:46 +0100 (Sun, 20 Jan 2008) | 2 lines #1648: add sys.gettrace() and sys.getprofile(). ........ r60139 | georg.brandl | 2008-01-20 15:17:42 +0100 (Sun, 20 Jan 2008) | 2 lines #1669: don't allow shutil.rmtree() to be called on a symlink. ........ r60140 | georg.brandl | 2008-01-20 15:20:02 +0100 (Sun, 20 Jan 2008) | 2 lines Fix test_pyclbr after urllib change. ........ r60141 | christian.heimes | 2008-01-20 15:28:28 +0100 (Sun, 20 Jan 2008) | 1 line Fixed a wrong assumption in configure.in and Include/pyport.h. The is finite function is not called isfinite() but finite(). Sorry, my fault. :) ........ r60142 | georg.brandl | 2008-01-20 15:31:27 +0100 (Sun, 20 Jan 2008) | 2 lines #1876: fix typos in test_operator. ........
2008-01-20 11:14:11 -04:00
.. 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`.
.. note::
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
2007-08-15 11:28:22 -03:00
.. function:: getwindowsversion()
Return a tuple containing five components, describing the Windows version
currently running. The elements are *major*, *minor*, *build*, *platform*, and
*text*. *text* contains a string while all other values are integers.
*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 |
+-----------------------------------------+-----------------------+
| :const:`3 (VER_PLATFORM_WIN32_CE)` | Windows CE |
+-----------------------------------------+-----------------------+
This function wraps the Win32 :cfunc:`GetVersionEx` function; see the Microsoft
documentation for more information about these fields.
Availability: Windows.
.. 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.
.. function:: intern(string)
Enter *string* in the table of "interned" strings and return the interned string
-- which is *string* itself or a copy. Interning strings is useful to gain a
little performance on dictionary lookup -- if the keys in a dictionary are
interned, and the lookup key is interned, the key comparisons (after hashing)
can be done by a pointer compare instead of a string compare. Normally, the
names used in Python programs are automatically interned, and the dictionaries
used to hold module, class or instance attributes have interned keys.
Interned strings are not immortal; you must keep a reference to the return
value of :func:`intern` around to benefit from it.
2007-08-15 11:28:22 -03:00
.. 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:: maxsize
2007-08-15 11:28:22 -03:00
2007-12-15 05:55:35 -04:00
An integer giving the maximum value a variable of type :ctype:`Py_ssize_t` can
take. It's usually ``2**31 - 1`` on a 32-bit platform and ``2**63 - 1`` on a
64-bit platform.
2007-08-15 11:28:22 -03:00
.. 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:: modules
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.
.. 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.
.. data:: platform
Merged revisions 60124-60142 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60131 | georg.brandl | 2008-01-20 12:13:29 +0100 (Sun, 20 Jan 2008) | 3 lines #1351692: in pprint, always call format() for dict and list items to enable custom formatting of contents via subclassing PrettyPrinter. ........ r60133 | georg.brandl | 2008-01-20 12:43:03 +0100 (Sun, 20 Jan 2008) | 2 lines #1178141: add addinfourl.code to get http status code from urllib. ........ r60134 | georg.brandl | 2008-01-20 13:05:43 +0100 (Sun, 20 Jan 2008) | 4 lines #856047: respect the ``no_proxy`` env var when checking for proxies in urllib and using the other ``_proxy`` env vars. Original patch by Donovan Baarda. ........ r60135 | georg.brandl | 2008-01-20 13:18:17 +0100 (Sun, 20 Jan 2008) | 4 lines #1664522: in urllib, don't read non-existing directories in ftp mode, returning a 0-byte file -- raise an IOError instead. Original patch from Phil Knirsch. ........ r60136 | georg.brandl | 2008-01-20 13:57:47 +0100 (Sun, 20 Jan 2008) | 2 lines #799369: document possible sys.platform values. ........ r60137 | georg.brandl | 2008-01-20 14:08:37 +0100 (Sun, 20 Jan 2008) | 2 lines #652749: document the constants added to the builtins by site.py. ........ r60138 | georg.brandl | 2008-01-20 14:59:46 +0100 (Sun, 20 Jan 2008) | 2 lines #1648: add sys.gettrace() and sys.getprofile(). ........ r60139 | georg.brandl | 2008-01-20 15:17:42 +0100 (Sun, 20 Jan 2008) | 2 lines #1669: don't allow shutil.rmtree() to be called on a symlink. ........ r60140 | georg.brandl | 2008-01-20 15:20:02 +0100 (Sun, 20 Jan 2008) | 2 lines Fix test_pyclbr after urllib change. ........ r60141 | christian.heimes | 2008-01-20 15:28:28 +0100 (Sun, 20 Jan 2008) | 1 line Fixed a wrong assumption in configure.in and Include/pyport.h. The is finite function is not called isfinite() but finite(). Sorry, my fault. :) ........ r60142 | georg.brandl | 2008-01-20 15:31:27 +0100 (Sun, 20 Jan 2008) | 2 lines #1876: fix typos in test_operator. ........
2008-01-20 11:14:11 -04:00
This string contains a platform identifier that can be used to append
platform-specific components to :data:`sys.path`, for instance.
For 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'`` or ``'linux2'``, *at the time when Python was built*.
For other systems, the values are:
================ ===========================
System :data:`platform` value
================ ===========================
Windows ``'win32'``
Windows/Cygwin ``'cygwin'``
MacOS X ``'darwin'``
MacOS 9 ``'mac'``
OS/2 ``'os2'``
OS/2 EMX ``'os2emx'``
RiscOS ``'riscos'``
AtheOS ``'atheos'``
================ ===========================
2007-08-15 11:28:22 -03:00
.. 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 :option:`--prefix`
argument to the :program:`configure` script. The main collection of Python
library modules is installed in the directory ``prefix + '/lib/pythonversion'``
while the platform independent header files (all except :file:`pyconfig.h`) are
stored in ``prefix + '/include/pythonversion'``, where *version* is equal to
``version[:3]``.
.. 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.
Merged revisions 59822-59841 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59822 | georg.brandl | 2008-01-07 17:43:47 +0100 (Mon, 07 Jan 2008) | 2 lines Restore "somenamedtuple" as the "class" for named tuple attrs. ........ r59824 | georg.brandl | 2008-01-07 18:09:35 +0100 (Mon, 07 Jan 2008) | 2 lines Patch #602345 by Neal Norwitz and me: add -B option and PYTHONDONTWRITEBYTECODE envvar to skip writing bytecode. ........ r59827 | georg.brandl | 2008-01-07 18:25:53 +0100 (Mon, 07 Jan 2008) | 2 lines patch #1668: clarify envvar docs; rename THREADDEBUG to PYTHONTHREADDEBUG. ........ r59830 | georg.brandl | 2008-01-07 19:16:36 +0100 (Mon, 07 Jan 2008) | 2 lines Make Python compile with --disable-unicode. ........ r59831 | georg.brandl | 2008-01-07 19:23:27 +0100 (Mon, 07 Jan 2008) | 2 lines Restructure urllib doc structure. ........ r59833 | georg.brandl | 2008-01-07 19:41:34 +0100 (Mon, 07 Jan 2008) | 2 lines Fix #define ordering. ........ r59834 | georg.brandl | 2008-01-07 19:47:44 +0100 (Mon, 07 Jan 2008) | 2 lines #467924, patch by Alan McIntyre: Add ZipFile.extract and ZipFile.extractall. ........ r59835 | raymond.hettinger | 2008-01-07 19:52:19 +0100 (Mon, 07 Jan 2008) | 1 line Fix inconsistent title levels -- it made the whole doc build crash horribly. ........ r59836 | georg.brandl | 2008-01-07 19:57:03 +0100 (Mon, 07 Jan 2008) | 2 lines Fix two further doc build warnings. ........ r59837 | georg.brandl | 2008-01-07 20:17:10 +0100 (Mon, 07 Jan 2008) | 2 lines Clarify metaclass docs and add example. ........ r59838 | vinay.sajip | 2008-01-07 20:40:10 +0100 (Mon, 07 Jan 2008) | 1 line Added section about adding contextual information to log output. ........ r59839 | christian.heimes | 2008-01-07 20:58:41 +0100 (Mon, 07 Jan 2008) | 1 line Fixed indention problem that caused the second TIPC test to run on systems without TIPC ........ r59840 | raymond.hettinger | 2008-01-07 21:07:38 +0100 (Mon, 07 Jan 2008) | 1 line Cleanup named tuple subclassing example. ........
2008-01-07 17:14:23 -04:00
.. 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 ``-B`` command line option and the ``PYTHONDONTWRITEBYTECODE``
environment variable, but you can set it yourself to control bytecode file
generation.
.. versionadded:: 2.6
2007-08-15 11:28:22 -03:00
.. 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.
2007-08-15 11:28:22 -03:00
.. function:: setdlopenflags(n)
Set the flags used by the interpreter for :cfunc:`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.
.. 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 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``.
.. 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. See section :ref:`debugger-hooks` in the
chapter on the Python debugger. The function is thread-specific; for a
debugger to support multiple threads, it must be registered using
:func:`settrace` for each thread being debugged.
.. note::
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 :option:`--with-tsc`. To understand
the output of this dump, read :file:`Python/ceval.c` in the Python sources.
.. data:: stdin
stdout
stderr
File objects corresponding to the interpreter's standard input, output and error
Merged revisions 59259-59274 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines Issue #1531: Read fileobj from the current offset, do not seek to the start. (will backport to 2.5) ........ r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines Document PyEval_* functions from ceval.c. Credits to Michael Sloan from GHOP. ........ r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines Add a few refcount data entries. ........ r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines Add test suite for cmd module. Written by Michael Schneider for GHOP. ........ r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines Add examples to the ElementTree documentation. Written by h4wk.cz for GHOP. ........ r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines Add "Using Python on Windows" document, by Robert Lehmann. Written for GHOP. ........ r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines Add example to mmap docs. Written for GHOP by Rafal Rawicki. ........ r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines Convert bdb.rst line endings to Unix style. ........ r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines Add more entries to the glossary. Written by Jeff Wheeler for GHOP. ........
2007-12-02 11:22:16 -04:00
streams. ``stdin`` is used for all interpreter input except for scripts but
including calls to :func:`input`. ``stdout`` is used for
the output of :func:`print` and :term:`expression` statements and for the
prompts of :func:`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.)
2007-08-15 11:28:22 -03:00
.. 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 restore the actual files to known working file objects in
case they have been overwritten with a broken object.
.. note::
Under some conditions ``stdin``, ``stdout`` and ``stderr`` as well as the
original values ``__stdin__``, ``__stdout__`` and ``__stderr__`` can be
None. It is usually the case for Windows GUI apps that aren't connected to
a console and Python apps started with :program:`pythonw`.
2007-08-15 11:28:22 -03:00
.. 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. It has a value of the form
``'version (#build_number, build_date, build_time) [compiler]'``. The first
three characters are used to identify the version in the installation
directories (where appropriate on each platform). An example::
>>> import sys
>>> sys.version
'1.5.2 (#0 Apr 13 1999, 10:51:12) [MSC 32 bit (Intel)]'
.. data:: api_version
The C API version for this interpreter. Programmers may find this useful when
debugging version conflicts between Python and extension modules.
.. 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)``.
.. 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.
.. seealso::
Module :mod:`site`
This describes how to use .pth files to extend ``sys.path``.