mirror of
https://github.com/python/cpython.git
synced 2025-10-31 10:26:02 +00:00
a62da1daaf
svn+ssh://pythondev@svn.python.org/python/trunk ........ r59923 | raymond.hettinger | 2008-01-11 19:04:55 +0100 (Fri, 11 Jan 2008) | 1 line Speed-up and simplify code urlparse's result objects. ........ r59924 | andrew.kuchling | 2008-01-11 20:33:24 +0100 (Fri, 11 Jan 2008) | 1 line Bug #1790: update link; remove outdated paragraph ........ r59925 | thomas.heller | 2008-01-11 20:34:06 +0100 (Fri, 11 Jan 2008) | 5 lines Raise an error instead of crashing with a segfault when a NULL function pointer is called. Will backport to release25-maint. ........ r59927 | thomas.heller | 2008-01-11 21:29:19 +0100 (Fri, 11 Jan 2008) | 4 lines Fix a potential 'SystemError: NULL result without error'. NULL may be a valid return value from PyLong_AsVoidPtr. Will backport to release25-maint. ........ r59928 | raymond.hettinger | 2008-01-12 00:25:18 +0100 (Sat, 12 Jan 2008) | 1 line Update the opcode docs for STORE_MAP and BUILD_MAP ........ r59929 | mark.dickinson | 2008-01-12 02:56:00 +0100 (Sat, 12 Jan 2008) | 4 lines Issue 1780: Allow leading and trailing whitespace in Decimal constructor, when constructing from a string. Disallow trailing newlines in Context.create_decimal. ........ r59930 | georg.brandl | 2008-01-12 11:53:29 +0100 (Sat, 12 Jan 2008) | 3 lines Move OSError docs to exceptions doc, remove obsolete descriptions from os docs, rework posix docs. ........ r59931 | georg.brandl | 2008-01-12 14:47:57 +0100 (Sat, 12 Jan 2008) | 3 lines Patch #1700288: Method cache optimization, by Armin Rigo, ported to 2.6 by Kevin Jacobs. ........ r59932 | georg.brandl | 2008-01-12 17:11:09 +0100 (Sat, 12 Jan 2008) | 2 lines Fix editing glitch. ........
85 lines
3.4 KiB
ReStructuredText
85 lines
3.4 KiB
ReStructuredText
:mod:`posix` --- The most common POSIX system calls
|
|
===================================================
|
|
|
|
.. module:: posix
|
|
:platform: Unix
|
|
:synopsis: The most common POSIX system calls (normally used via module os).
|
|
|
|
|
|
This module provides access to operating system functionality that is
|
|
standardized by the C Standard and the POSIX standard (a thinly disguised Unix
|
|
interface).
|
|
|
|
.. index:: module: os
|
|
|
|
**Do not import this module directly.** Instead, import the module :mod:`os`,
|
|
which provides a *portable* version of this interface. On Unix, the :mod:`os`
|
|
module provides a superset of the :mod:`posix` interface. On non-Unix operating
|
|
systems the :mod:`posix` module is not available, but a subset is always
|
|
available through the :mod:`os` interface. Once :mod:`os` is imported, there is
|
|
*no* performance penalty in using it instead of :mod:`posix`. In addition,
|
|
:mod:`os` provides some additional functionality, such as automatically calling
|
|
:func:`putenv` when an entry in ``os.environ`` is changed.
|
|
|
|
Errors are reported as exceptions; the usual exceptions are given for type
|
|
errors, while errors reported by the system calls raise :exc:`OSError`.
|
|
|
|
|
|
.. _posix-large-files:
|
|
|
|
Large File Support
|
|
------------------
|
|
|
|
.. index::
|
|
single: large files
|
|
single: file; large files
|
|
|
|
.. sectionauthor:: Steve Clift <clift@mail.anacapa.net>
|
|
|
|
Several operating systems (including AIX, HP-UX, Irix and Solaris) provide
|
|
support for files that are larger than 2 GB from a C programming model where
|
|
:ctype:`int` and :ctype:`long` are 32-bit values. This is typically accomplished
|
|
by defining the relevant size and offset types as 64-bit values. Such files are
|
|
sometimes referred to as :dfn:`large files`.
|
|
|
|
Large file support is enabled in Python when the size of an :ctype:`off_t` is
|
|
larger than a :ctype:`long` and the :ctype:`long long` type is available and is
|
|
at least as large as an :ctype:`off_t`.
|
|
It may be necessary to configure and compile Python with certain compiler flags
|
|
to enable this mode. For example, it is enabled by default with recent versions
|
|
of Irix, but with Solaris 2.6 and 2.7 you need to do something like::
|
|
|
|
CFLAGS="`getconf LFS_CFLAGS`" OPT="-g -O2 $CFLAGS" \
|
|
./configure
|
|
|
|
On large-file-capable Linux systems, this might work::
|
|
|
|
CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \
|
|
./configure
|
|
|
|
|
|
.. _posix-contents:
|
|
|
|
Notable Module Contents
|
|
-----------------------
|
|
|
|
In addition to many functions described in the :mod:`os` module documentation,
|
|
:mod:`posix` defines the following data item:
|
|
|
|
.. data:: environ
|
|
|
|
A dictionary representing the string environment at the time the interpreter
|
|
was started. For example, ``environ['HOME']`` is the pathname of your home
|
|
directory, equivalent to ``getenv("HOME")`` in C.
|
|
|
|
Modifying this dictionary does not affect the string environment passed on by
|
|
:func:`execv`, :func:`popen` or :func:`system`; if you need to change the
|
|
environment, pass ``environ`` to :func:`execve` or add variable assignments and
|
|
export statements to the command string for :func:`system` or :func:`popen`.
|
|
|
|
.. note::
|
|
|
|
The :mod:`os` module provides an alternate implementation of ``environ`` which
|
|
updates the environment on modification. Note also that updating ``os.environ``
|
|
will render this dictionary obsolete. Use of the :mod:`os` module version of
|
|
this is recommended over direct access to the :mod:`posix` module.
|