diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/os.rst | 4 | ||||
| -rw-r--r-- | Doc/library/subprocess.rst | 88 | ||||
| -rw-r--r-- | Doc/whatsnew/2.7.rst | 6 |
3 files changed, 85 insertions, 13 deletions
diff --git a/Doc/library/os.rst b/Doc/library/os.rst index 9bb2fc6..90e59ef 100644 --- a/Doc/library/os.rst +++ b/Doc/library/os.rst @@ -1470,8 +1470,8 @@ written in Python, such as a mail server's external command delivery program. (Note that the :mod:`subprocess` module provides more powerful facilities for spawning new processes and retrieving their results; using that module is - preferable to using these functions. Check specially the *Replacing Older - Functions with the subprocess Module* section in that documentation page.) + preferable to using these functions. Check especially the + :ref:`subprocess-replacements` section.) If *mode* is :const:`P_NOWAIT`, this function returns the process id of the new process; if *mode* is :const:`P_WAIT`, returns the process's exit code if it diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 3318d43..d0e655d 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -412,8 +412,8 @@ Replacing shell pipeline output = p2.communicate()[0] -Replacing os.system() -^^^^^^^^^^^^^^^^^^^^^ +Replacing :func:`os.system` +^^^^^^^^^^^^^^^^^^^^^^^^^^^ :: @@ -440,8 +440,8 @@ A more realistic example would look like this:: print("Execution failed:", e, file=sys.stderr) -Replacing the os.spawn family -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Replacing the :func:`os.spawn <os.spawnl>` family +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ P_NOWAIT example:: @@ -468,17 +468,85 @@ Environment example:: Popen(["/bin/mycmd", "myarg"], env={"PATH": "/usr/bin"}) -Replacing os.popen -^^^^^^^^^^^^^^^^^^ + +Replacing :func:`os.popen`, :func:`os.popen2`, :func:`os.popen3` +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ :: - pipe = os.popen(cmd, 'r', bufsize) + (child_stdin, child_stdout) = os.popen2(cmd, mode, bufsize) ==> - pipe = Popen(cmd, shell=True, bufsize=bufsize, stdout=PIPE).stdout + p = Popen(cmd, shell=True, bufsize=bufsize, + stdin=PIPE, stdout=PIPE, close_fds=True) + (child_stdin, child_stdout) = (p.stdin, p.stdout) :: - pipe = os.popen(cmd, 'w', bufsize) + (child_stdin, + child_stdout, + child_stderr) = os.popen3(cmd, mode, bufsize) + ==> + p = Popen(cmd, shell=True, bufsize=bufsize, + stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True) + (child_stdin, + child_stdout, + child_stderr) = (p.stdin, p.stdout, p.stderr) + +:: + + (child_stdin, child_stdout_and_stderr) = os.popen4(cmd, mode, bufsize) + ==> + p = Popen(cmd, shell=True, bufsize=bufsize, + stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True) + (child_stdin, child_stdout_and_stderr) = (p.stdin, p.stdout) + +Return code handling translates as follows:: + + pipe = os.popen(cmd, 'w') + ... + rc = pipe.close() + if rc != None and rc % 256: + print "There were some errors" ==> - pipe = Popen(cmd, shell=True, bufsize=bufsize, stdin=PIPE).stdin + process = Popen(cmd, 'w', stdin=PIPE) + ... + process.stdin.close() + if process.wait() != 0: + print "There were some errors" + + +Replacing functions from the :mod:`popen2` module +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. note:: + + If the cmd argument to popen2 functions is a string, the command is executed + through /bin/sh. If it is a list, the command is directly executed. + +:: + + (child_stdout, child_stdin) = popen2.popen2("somestring", bufsize, mode) + ==> + p = Popen(["somestring"], shell=True, bufsize=bufsize, + stdin=PIPE, stdout=PIPE, close_fds=True) + (child_stdout, child_stdin) = (p.stdout, p.stdin) + +:: + + (child_stdout, child_stdin) = popen2.popen2(["mycmd", "myarg"], bufsize, mode) + ==> + p = Popen(["mycmd", "myarg"], bufsize=bufsize, + stdin=PIPE, stdout=PIPE, close_fds=True) + (child_stdout, child_stdin) = (p.stdout, p.stdin) + +:class:`popen2.Popen3` and :class:`popen2.Popen4` basically work as +:class:`subprocess.Popen`, except that: + +* :class:`Popen` raises an exception if the execution fails. + +* the *capturestderr* argument is replaced with the *stderr* argument. + +* ``stdin=PIPE`` and ``stdout=PIPE`` must be specified. + +* popen2 closes all file descriptors by default, but you have to specify + ``close_fds=True`` with :class:`Popen`. diff --git a/Doc/whatsnew/2.7.rst b/Doc/whatsnew/2.7.rst index 9182c453..f5f7d19 100644 --- a/Doc/whatsnew/2.7.rst +++ b/Doc/whatsnew/2.7.rst @@ -663,7 +663,11 @@ Porting to Python 2.7 This section lists previously described changes and other bugfixes that may require changes to your code: -To be written. +* Because of an optimization for the :keyword:`with` statement, the special + methods :meth:`__enter__` and :meth:`__exit__` must belong to the object's + type, and cannot be directly attached to the object's instance. This + affects new-style classes (derived from :class:`object`) and C extension + types. (:issue:`6101`.) .. ====================================================================== |