diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/subprocess.rst | 41 |
1 files changed, 36 insertions, 5 deletions
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index a7df536..aeff9f0 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -28,7 +28,7 @@ Using the subprocess Module This module defines one class called :class:`Popen`: -.. class:: Popen(args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0) +.. class:: Popen(args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0, restore_signals=True, start_new_session=False) Arguments are: @@ -41,7 +41,8 @@ This module defines one class called :class:`Popen`: name for the executing program in utilities such as :program:`ps`. On Unix, with *shell=False* (default): In this case, the Popen class uses - :meth:`os.execvp` to execute the child program. *args* should normally be a + :meth:`os.execvp` like behavior to execute the child program. + *args* should normally be a sequence. If a string is specified for *args*, it will be used as the name or path of the program to execute; this will only work if the program is being given no arguments. @@ -108,7 +109,23 @@ This module defines one class called :class:`Popen`: applications should be captured into the same file handle as for stdout. If *preexec_fn* is set to a callable object, this object will be called in the - child process just before the child is executed. (Unix only) + child process just before the child is executed. + (Unix only) + + .. warning:: + + The *preexec_fn* parameter is not safe to use in the presence of threads + in your application. The child process could deadlock before exec is + called. + If you must use it, keep it trivial! Minimize the number of libraries + you call into. + + .. note:: + + If you need to modify the environment for the child use the *env* + parameter rather than doing it in a *preexec_fn*. + The *start_new_session* parameter can take the place of a previously + common use of *preexec_fn* to call os.setsid() in the child. If *close_fds* is true, all file descriptors except :const:`0`, :const:`1` and :const:`2` will be closed before the child process is executed. (Unix only). @@ -124,9 +141,23 @@ This module defines one class called :class:`Popen`: searching the executable, so you can't specify the program's path relative to *cwd*. + If *restore_signals* is True (the default) all signals that Python has set to + SIG_IGN are restored to SIG_DFL in the child process before the exec. + Currently this includes the SIGPIPE, SIGXFZ and SIGXFSZ signals. + (Unix only) + + .. versionchanged:: 3.2 + *restore_signals* was added. + + If *start_new_session* is True the setsid() system call will be made in the + child process prior to the execution of the subprocess. (Unix only) + + .. versionchanged:: 3.2 + *start_new_session* was added. + If *env* is not ``None``, it must be a mapping that defines the environment - variables for the new process; these are used instead of inheriting the current - process' environment, which is the default behavior. + variables for the new process; these are used instead of the default + behavior of inheriting the current process' environment. .. note:: |