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Diffstat (limited to 'Doc/library/subprocess.rst')
| -rw-r--r-- | Doc/library/subprocess.rst | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 5ae6eb0..3458003 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -193,6 +193,10 @@ Instances of the :class:`Popen` class have the following methods: Wait for child process to terminate. Set and return :attr:`returncode` attribute. + warning:: This will deadlock if the child process generates enough output + to a stdout or stderr pipe causing it to block waiting for the OS's pipe + buffer to accept more data. + .. method:: Popen.communicate(input=None) @@ -250,18 +254,30 @@ The following attributes are also available: If the *stdin* argument is ``PIPE``, this attribute is a file object that provides input to the child process. Otherwise, it is ``None``. + warning:: Use :meth:`communicate` rather than .stdin.write() to avoid + deadlocks due to any of the other pipe buffers filling up and blocking the + child process. + .. attribute:: Popen.stdout If the *stdout* argument is ``PIPE``, this attribute is a file object that provides output from the child process. Otherwise, it is ``None``. + warning:: Use :meth:`communicate` rather than .stdout.read() to avoid + deadlocks due to any of the other pipe buffers filling up and blocking the + child process. + .. attribute:: Popen.stderr If the *stderr* argument is ``PIPE``, this attribute is file object that provides error output from the child process. Otherwise, it is ``None``. + warning:: Use :meth:`communicate` rather than .stderr.read() to avoid + deadlocks due to any of the other pipe buffers filling up and blocking the + child process. + .. attribute:: Popen.pid |