<!DOCTYPE html PUBLIC
"-//W3C//DTD HTML 4.0 Transitional//EN">
<link rel=
"STYLESHEET" href=
"lib.css" type='text/css'
/>
<link rel=
"SHORTCUT ICON" href=
"../icons/pyfav.png" type=
"image/png" />
<link rel='start' href='../index.html' title='Python Documentation Index'
/>
<link rel=
"first" href=
"lib.html" title='Python Library Reference'
/>
<link rel='contents' href='contents.html'
title=
"Contents" />
<link rel='index' href='genindex.html' title='Index'
/>
<link rel='last' href='about.html' title='About this document...'
/>
<link rel='help' href='about.html' title='About this document...'
/>
<link rel=
"next" href=
"module-pwd.html" />
<link rel=
"prev" href=
"unix.html" />
<link rel=
"parent" href=
"unix.html" />
<link rel=
"next" href=
"posix-large-files.html" />
<meta name='aesop' content='information'
/>
<title>8.1 posix -- The most common POSIX system calls
</title>
<div id='top-navigation-panel' xml:id='top-navigation-panel'
>
<table align=
"center" width=
"100%" cellpadding=
"0" cellspacing=
"2">
<td class='online-navigation'
><a rel=
"prev" title=
"8. Unix Specific Services"
href=
"unix.html"><img src='../icons/previous.png'
border='
0' height='
32' alt='Previous Page' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"parent" title=
"8. Unix Specific Services"
href=
"unix.html"><img src='../icons/up.png'
border='
0' height='
32' alt='Up One Level' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"next" title=
"8.1.1 Large File Support"
href=
"posix-large-files.html"><img src='../icons/next.png'
border='
0' height='
32' alt='Next Page' width='
32'
/></A></td>
<td align=
"center" width=
"100%">Python Library Reference
</td>
<td class='online-navigation'
><a rel=
"contents" title=
"Table of Contents"
href=
"contents.html"><img src='../icons/contents.png'
border='
0' height='
32' alt='Contents' width='
32'
/></A></td>
<td class='online-navigation'
><a href=
"modindex.html" title=
"Module Index"><img src='../icons/modules.png'
border='
0' height='
32' alt='Module Index' width='
32'
/></a></td>
<td class='online-navigation'
><a rel=
"index" title=
"Index"
href=
"genindex.html"><img src='../icons/index.png'
border='
0' height='
32' alt='Index' width='
32'
/></A></td>
<div class='online-navigation'
>
<b class=
"navlabel">Previous:
</b>
<a class=
"sectref" rel=
"prev" href=
"unix.html">8. Unix Specific Services
</A>
<b class=
"navlabel">Up:
</b>
<a class=
"sectref" rel=
"parent" href=
"unix.html">8. Unix Specific Services
</A>
<b class=
"navlabel">Next:
</b>
<a class=
"sectref" rel=
"next" href=
"posix-large-files.html">8.1.1 Large File Support
</A>
<!--End of Navigation Panel-->
<H1><A NAME=
"SECTION0010100000000000000000">
8.1 <tt class=
"module">posix
</tt> --
The most common POSIX system calls
</A>
<A NAME=
"module-posix"></A>
<p class=
"availability">Availability:
<span
class=
"platform">Unix
</span>.
</p>
This module provides access to operating system functionality that is
standardized by the C Standard and the POSIX standard (a thinly
disguised
<span class=
"Unix">Unix
</span> interface).
<strong>Do not import this module directly.
</strong> Instead, import the
module
<tt class=
"module"><a href=
"module-os.html">os
</a></tt>, which provides a
<em>portable
</em> version of this
interface. On
<span class=
"Unix">Unix
</span>, the
<tt class=
"module"><a href=
"module-os.html">os
</a></tt> module provides a superset of
the
<tt class=
"module">posix
</tt> interface. On non-
<span class=
"Unix">Unix
</span> operating systems the
<tt class=
"module">posix
</tt> module is not available, but a subset is always
available through the
<tt class=
"module"><a href=
"module-os.html">os
</a></tt> interface. Once
<tt class=
"module"><a href=
"module-os.html">os
</a></tt> is
imported, there is
<em>no
</em> performance penalty in using it instead
of
<tt class=
"module">posix
</tt>. In addition,
<tt class=
"module"><a href=
"module-os.html">os
</a></tt><a id='l2h-
2969' xml:id='l2h-
2969'
></a>
provides some additional functionality, such as automatically calling
<tt class=
"function">putenv()
</tt> when an entry in
<code>os.environ
</code> is changed.
The descriptions below are very terse; refer to the corresponding
<span class=
"Unix">Unix
</span> manual (or POSIX documentation) entry for more information.
Arguments called
<var>path
</var> refer to a pathname given as a string.
Errors are reported as exceptions; the usual exceptions are given for
type errors, while errors reported by the system calls raise
<tt class=
"exception">error
</tt> (a synonym for the standard exception
<tt class=
"exception">OSError
</tt>), described below.
<p><br /></p><hr class='online-navigation'
/>
<div class='online-navigation'
>
<!--Table of Child-Links-->
<A NAME=
"CHILD_LINKS"><STRONG>Subsections
</STRONG></a>
<LI><A href=
"posix-large-files.html">8.1.1 Large File Support
</a>
<LI><A href=
"posix-contents.html">8.1.2 Module Contents
</a>
<!--End of Table of Child-Links-->
<div class='online-navigation'
>
<table align=
"center" width=
"100%" cellpadding=
"0" cellspacing=
"2">
<td class='online-navigation'
><a rel=
"prev" title=
"8. Unix Specific Services"
href=
"unix.html"><img src='../icons/previous.png'
border='
0' height='
32' alt='Previous Page' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"parent" title=
"8. Unix Specific Services"
href=
"unix.html"><img src='../icons/up.png'
border='
0' height='
32' alt='Up One Level' width='
32'
/></A></td>
<td class='online-navigation'
><a rel=
"next" title=
"8.1.1 Large File Support"
href=
"posix-large-files.html"><img src='../icons/next.png'
border='
0' height='
32' alt='Next Page' width='
32'
/></A></td>
<td align=
"center" width=
"100%">Python Library Reference
</td>
<td class='online-navigation'
><a rel=
"contents" title=
"Table of Contents"
href=
"contents.html"><img src='../icons/contents.png'
border='
0' height='
32' alt='Contents' width='
32'
/></A></td>
<td class='online-navigation'
><a href=
"modindex.html" title=
"Module Index"><img src='../icons/modules.png'
border='
0' height='
32' alt='Module Index' width='
32'
/></a></td>
<td class='online-navigation'
><a rel=
"index" title=
"Index"
href=
"genindex.html"><img src='../icons/index.png'
border='
0' height='
32' alt='Index' width='
32'
/></A></td>
<div class='online-navigation'
>
<b class=
"navlabel">Previous:
</b>
<a class=
"sectref" rel=
"prev" href=
"unix.html">8. Unix Specific Services
</A>
<b class=
"navlabel">Up:
</b>
<a class=
"sectref" rel=
"parent" href=
"unix.html">8. Unix Specific Services
</A>
<b class=
"navlabel">Next:
</b>
<a class=
"sectref" rel=
"next" href=
"posix-large-files.html">8.1.1 Large File Support
</A>
<span class=
"release-info">Release
2.4.2, documentation updated on
28 September
2005.
</span>
<!--End of Navigation Panel-->
See
<i><a href=
"about.html">About this document...
</a></i> for information on suggesting changes.