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Document that on Unix, the 'cmd' argument to the os.popen2/3/4 and

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popen2.popen2/3/4 functions can be a sequence. All texts are a variation on the
following:

On \UNIX, \var{cmd} may be a sequence, in which case arguments will be passed
directly to the program without shell intervention (as with
\function{os.spawnv()}). If \var{cmd} is a string it will be passed to the shell
(as with \function{os.system()}).
This commit is contained in:
Johannes Gijsbers 2004-10-11 18:12:20 +00:00
parent c054a8b1a9
commit 9fc9789a0d
4 changed files with 75 additions and 27 deletions
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12
Doc/lib/libos.tex
View file

@ -361,6 +361,11 @@ specified, it specifies the buffer size for the I/O pipes.
objects should be opened in binary or text mode. The default value
for \var{mode} is \code{'t'}.
Also, for each of these variants, on \UNIX, \var{cmd} may be a sequence, in
which case arguments will be passed directly to the program without shell
intervention (as with \function{os.spawnv()}). If \var{cmd} is a string it will
be passed to the shell (as with \function{os.system()}).
These methods do not make it possible to retrieve the return code from
the child processes. The only way to control the input and output
streams and also retrieve the return codes is to use the
@ -389,15 +394,14 @@ Availability: \UNIX, Windows.
\begin{funcdesc}{popen4}{cmd\optional{, mode\optional{, bufsize}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdin}, \var{child_stdout_and_stderr})}.
Availability: \UNIX, Windows.
\versionadded{2.0}
\end{funcdesc}
(Note that \code{\var{child_stdin}, \var{child_stdout}, and
\var{child_stderr}} are named from the point of view of the child
process, i.e. \var{child_stdin} is the child's standard input.)
Availability: \UNIX, Windows.
\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.

6
Doc/lib/libpopen2.tex
View file

@ -24,6 +24,11 @@ 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'}.
On \UNIX, \var{cmd} may be a sequence, in which case arguments will be passed
directly to the program without shell intervention (as with
\function{os.spawnv()}). If \var{cmd} is a string it will be passed to the
shell (as with \function{os.system()}).
The only way to retrieve the return codes for the child processes is
by using the \method{poll()} or \method{wait()} methods on the
\class{Popen3} and \class{Popen4} classes; these are only available on
@ -75,7 +80,6 @@ using \function{popen4()}.
\versionadded{2.0}
\end{classdesc}
\subsection{Popen3 and Popen4 Objects \label{popen3-objects}}
Instances of the \class{Popen3} and \class{Popen4} classes have the

18
Lib/os.py
View file

@ -611,6 +611,12 @@ def spawnlpe(mode, file, *args):
if _exists("fork"):
if not _exists("popen2"):
def popen2(cmd, mode="t", bufsize=-1):
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
may be a sequence, in which case arguments will be passed directly to
the program without shell intervention (as with os.spawnv()). If 'cmd'
is a string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdin, child_stdout) are returned."""
import popen2
stdout, stdin = popen2.popen2(cmd, bufsize)
return stdin, stdout
@ -618,6 +624,12 @@ def popen2(cmd, mode="t", bufsize=-1):
if not _exists("popen3"):
def popen3(cmd, mode="t", bufsize=-1):
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
may be a sequence, in which case arguments will be passed directly to
the program without shell intervention (as with os.spawnv()). If 'cmd'
is a string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdin, child_stdout, child_stderr) are returned."""
import popen2
stdout, stdin, stderr = popen2.popen3(cmd, bufsize)
return stdin, stdout, stderr
@ -625,6 +637,12 @@ def popen3(cmd, mode="t", bufsize=-1):
if not _exists("popen4"):
def popen4(cmd, mode="t", bufsize=-1):
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd'
may be a sequence, in which case arguments will be passed directly to
the program without shell intervention (as with os.spawnv()). If 'cmd'
is a string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdin, child_stdout_stderr) are returned."""
import popen2
stdout, stdin = popen2.popen4(cmd, bufsize)
return stdin, stdout

66
Lib/popen2.py
View file

@ -30,10 +30,14 @@ class Popen3:
def __init__(self, cmd, capturestderr=False, bufsize=-1):
"""The parameter 'cmd' is the shell command to execute in a
sub-process. The 'capturestderr' flag, if true, specifies that
the object should capture standard error output of the child process.
The default is false. If the 'bufsize' parameter is specified, it
specifies the size of the I/O buffers to/from the child process."""
sub-process. On UNIX, 'cmd' may be a sequence, in which case arguments
will be passed directly to the program without shell intervention (as
with os.spawnv()). If 'cmd' is a string it will be passed to the shell
(as with os.system()). The 'capturestderr' flag, if true, specifies
that the object should capture standard error output of the child
process. The default is false. If the 'bufsize' parameter is
specified, it specifies the size of the I/O buffers to/from the child
process."""
_cleanup()
p2cread, p2cwrite = os.pipe()
c2pread, c2pwrite = os.pipe()
@ -120,44 +124,62 @@ def __init__(self, cmd, bufsize=-1):
del Popen3, Popen4
def popen2(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout, child_stdin) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout, child_stdin) are returned."""
w, r = os.popen2(cmd, mode, bufsize)
return r, w
def popen3(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout, child_stdin, child_stderr) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout, child_stdin, child_stderr) are returned."""
w, r, e = os.popen3(cmd, mode, bufsize)
return r, w, e
def popen4(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout_stderr, child_stdin) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout_stderr, child_stdin) are returned."""
w, r = os.popen4(cmd, mode, bufsize)
return r, w
else:
def popen2(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout, child_stdin) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout, child_stdin) are returned."""
inst = Popen3(cmd, False, bufsize)
return inst.fromchild, inst.tochild
def popen3(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout, child_stdin, child_stderr) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout, child_stdin, child_stderr) are returned."""
inst = Popen3(cmd, True, bufsize)
return inst.fromchild, inst.tochild, inst.childerr
def popen4(cmd, bufsize=-1, mode='t'):
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
specified, it sets the buffer size for the I/O pipes. The file objects
(child_stdout_stderr, child_stdin) are returned."""
"""Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
be a sequence, in which case arguments will be passed directly to the
program without shell intervention (as with os.spawnv()). If 'cmd' is a
string it will be passed to the shell (as with os.system()). If
'bufsize' is specified, it sets the buffer size for the I/O pipes. The
file objects (child_stdout_stderr, child_stdin) are returned."""
inst = Popen4(cmd, bufsize)
return inst.fromchild, inst.tochild