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+\section{\module{posix} ---
+         The most common \POSIX{} system calls}
+
+\declaremodule{builtin}{posix}
+  \platform{Unix}
+\modulesynopsis{The most common \POSIX\ system calls (normally used
+                via module \refmodule{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).
+
+\strong{Do not import this module directly.}  Instead, import the
+module \refmodule{os}, which provides a \emph{portable} version of this
+interface.  On \UNIX, the \refmodule{os} module provides a superset of
+the \module{posix} interface.  On non-\UNIX{} operating systems the
+\module{posix} module is not available, but a subset is always
+available through the \refmodule{os} interface.  Once \refmodule{os} is
+imported, there is \emph{no} performance penalty in using it instead
+of \module{posix}.  In addition, \refmodule{os}\refstmodindex{os}
+provides some additional functionality, such as automatically calling
+\function{putenv()} when an entry in \code{os.environ} is changed.
+
+The descriptions below are very terse; refer to the corresponding
+\UNIX{} manual (or \POSIX{} documentation) entry for more information.
+Arguments called \var{path} 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
+\exception{error} (a synonym for the standard exception
+\exception{OSError}), described below.
+
+
+\subsection{Large File Support \label{posix-large-files}}
+\sectionauthor{Steve Clift}{clift@mail.anacapa.net}
+\index{large files}
+\index{file!large files}
+
+
+Several operating systems (including AIX, HPUX, 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}. Python
+longs are then used to represent file sizes, offsets and other values
+that can exceed the range of a Python int. 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:
+
+\begin{verbatim}
+CFLAGS="`getconf LFS_CFLAGS`" OPT="-g -O2 $CFLAGS" \
+        ./configure
+\end{verbatim} % $ <-- bow to font-lock
+
+On large-file-capable Linux systems, this might work:
+
+\begin{verbatim}
+CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \
+        ./configure
+\end{verbatim} % $ <-- bow to font-lock
+
+
+\subsection{Module Contents \label{posix-contents}}
+
+
+Module \module{posix} defines the following data item:
+
+\begin{datadesc}{environ}
+A dictionary representing the string environment at the time the
+interpreter was started. For example, \code{environ['HOME']} is the
+pathname of your home directory, equivalent to
+\code{getenv("HOME")} in C.
+
+Modifying this dictionary does not affect the string environment
+passed on by \function{execv()}, \function{popen()} or
+\function{system()}; if you need to change the environment, pass
+\code{environ} to \function{execve()} or add variable assignments and
+export statements to the command string for \function{system()} or
+\function{popen()}.
+
+\note{The \refmodule{os} module provides an alternate
+implementation of \code{environ} which updates the environment on
+modification.  Note also that updating \code{os.environ} will render
+this dictionary obsolete.  Use of the \refmodule{os} module version of
+this is recommended over direct access to the \module{posix} module.}
+\end{datadesc}
+
+Additional contents of this module should only be accessed via the
+\refmodule{os} module; refer to the documentation for that module for
+further information.