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Updated documentation relating to the various flavors of popen[234]() 

for Windows & Unix.
This commit is contained in:
Fred Drake 2000-09-28 20:27:51 +00:00
parent 18b9b93df3
commit 8a9db99760
2 changed files with 79 additions and 24 deletions
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30
Doc/lib/libos.tex
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@ -296,6 +296,36 @@ Availability: \UNIX{}.
\end{funcdesc} \end{funcdesc}
For each of these \function{popen()} variants, if \var{bufsize} is
specified, it specifies the buffer size for the I/O pipes.
\var{mode}, if provided, should be the string \code{'b'} or
\code{'t'}; on Windows this is needed to determine whether the file
objects should be opened in binary or text mode. The default value
for \var{mode} is \code{'t'}.
\begin{funcdesc}{popen2}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdin}, \var{child_stdout})}.
\versionadded{2.0}
\end{funcdesc}
\begin{funcdesc}{popen3}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdin}, \var{child_stdout}, \var{child_stderr})}.
\versionadded{2.0}
\end{funcdesc}
\begin{funcdesc}{popen4}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdin}, \var{child_stdout_and_stderr})}.
\versionadded{2.0}
\end{funcdesc}
This functionality is also available in the \refmodule{popen2} module
using functions of the same names, but the return values of those
functions have a different order.
\subsection{File Descriptor Operations \label{os-fd-ops}} \subsection{File Descriptor Operations \label{os-fd-ops}}
These functions operate on I/O streams referred to These functions operate on I/O streams referred to

73
Doc/lib/libpopen2.tex
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@ -2,39 +2,53 @@
Subprocesses with accessible I/O streams} Subprocesses with accessible I/O streams}
\declaremodule{standard}{popen2} \declaremodule{standard}{popen2}
\platform{Unix} \platform{Unix, Windows}
\modulesynopsis{Subprocesses with accessible standard I/O streams.} \modulesynopsis{Subprocesses with accessible standard I/O streams.}
\sectionauthor{Drew Csillag}{drew_csillag@geocities.com} \sectionauthor{Drew Csillag}{drew_csillag@geocities.com}
This module allows you to spawn processes and connect their This module allows you to spawn processes and connect to their
input/output/error pipes and obtain their return codes under \UNIX. input/output/error pipes and obtain their return codes under
Similar functionality exists for Windows platforms using the \UNIX{} and Windows.
\module{win32pipe} module provided as part of Mark Hammond's Windows
extensions.
The primary interface offered by this module is a pair of factory Note that starting with Python 2.0, this functionality is available
functions: using functions from the \refmodule{os} module which have the same
names as the factory functions here, but the order of the return
values is more intuitive in the \refmodule{os} module variants.
\begin{funcdesc}{popen2}{cmd\optional{, bufsize}} The primary interface offered by this module is a trio of factory
Executes \var{cmd} as a sub-process. If \var{bufsize} is specified, functions. For each of these, if \var{bufsize} is specified,
it specifies the buffer size for the I/O pipes. Returns the file it specifies the buffer size for the I/O pipes. \var{mode}, if
objects \code{(\var{child_stdout}, \var{child_stdin})}. provided, should be the string \code{'b'} or \code{'t'}; on Windows
this is needed to determine whether the file objects should be opened
in binary or text mode. The default value for \var{mode} is
\code{'t'}.
\begin{funcdesc}{popen2}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdout}, \var{child_stdin})}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{popen3}{cmd\optional{, bufsize}} \begin{funcdesc}{popen3}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. If \var{bufsize} is specified, Executes \var{cmd} as a sub-process. Returns the file objects
it specifies the buffer size for the I/O pipes. Returns the file \code{(\var{child_stdout}, \var{child_stdin}, \var{child_stderr})}.
objects \code{(\var{child_stdout}, \var{child_stdin},
\var{child_stderr})}.
\end{funcdesc} \end{funcdesc}
The class defining the objects returned by the factory functions is \begin{funcdesc}{popen4}{cmd\optional{, bufsize\optional{, mode}}}
also available: Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdout_and_stderr}, \var{child_stdin})}.
\versionadded{2.0}
\end{funcdesc}
On \UNIX, a class defining the objects returned by the factory
functions is also available. These are not used for the Windows
implementation, and are not available on that platform.
\begin{classdesc}{Popen3}{cmd\optional{, capturestderr\optional{, bufsize}}} \begin{classdesc}{Popen3}{cmd\optional{, capturestderr\optional{, bufsize}}}
This class represents a child process. Normally, \class{Popen3} This class represents a child process. Normally, \class{Popen3}
instances are created using the factory functions described above. instances are created using the \function{popen2()} and
\function{popen3()} factory functions described above.
If not using one off the helper functions to create \class{Popen3} If not using one off the helper functions to create \class{Popen3}
objects, the parameter \var{cmd} is the shell command to execute in a objects, the parameter \var{cmd} is the shell command to execute in a
@ -44,10 +58,18 @@ The default is false. If the \var{bufsize} parameter is specified, it
specifies the size of the I/O buffers to/from the child process. specifies the size of the I/O buffers to/from the child process.
\end{classdesc} \end{classdesc}
\begin{classdesc}{Popen4}{cmd\optional{, bufsize}}
Similar to \class{Popen3}, but always captures standard error into the
same file object as standard output. These are typically created
using \function{popen4()}.
\versionadded{2.0}
\end{classdesc}
\subsection{Popen3 Objects \label{popen3-objects}}
Instances of the \class{Popen3} class have the following methods: \subsection{Popen3 and Popen4 Objects \label{popen3-objects}}
Instances of the \class{Popen3} and \class{Popen4} classes have the
following methods:
\begin{methoddesc}{poll}{} \begin{methoddesc}{poll}{}
Returns \code{-1} if child process hasn't completed yet, or its return Returns \code{-1} if child process hasn't completed yet, or its return
@ -59,10 +81,12 @@ Waits for and returns the return code of the child process.
\end{methoddesc} \end{methoddesc}
The following attributes of \class{Popen3} objects are also available: The following attributes are also available:
\begin{memberdesc}{fromchild} \begin{memberdesc}{fromchild}
A file object that provides output from the child process. A file object that provides output from the child process. For
\class{Popen4} instances, this will provide both the standard output
and standard error streams.
\end{memberdesc} \end{memberdesc}
\begin{memberdesc}{tochild} \begin{memberdesc}{tochild}
@ -72,6 +96,7 @@ A file object that provides input to the child process.
\begin{memberdesc}{childerr} \begin{memberdesc}{childerr}
Where the standard error from the child process goes is Where the standard error from the child process goes is
\var{capturestderr} was true for the constructor, or \code{None}. \var{capturestderr} was true for the constructor, or \code{None}.
This will always be \code{None} for \class{Popen4} instances.
\end{memberdesc} \end{memberdesc}
\begin{memberdesc}{pid} \begin{memberdesc}{pid}