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Diffstat (limited to 'Doc/library/subprocess.rst')
| -rw-r--r-- | Doc/library/subprocess.rst | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 05d09e304b3..028a7861f36 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -1525,6 +1525,24 @@ handling consistency are valid for these functions. Notes ----- +.. _subprocess-timeout-behavior: + +Timeout Behavior +^^^^^^^^^^^^^^^^ + +When using the ``timeout`` parameter in functions like :func:`run`, +:meth:`Popen.wait`, or :meth:`Popen.communicate`, +users should be aware of the following behaviors: + +1. **Process Creation Delay**: The initial process creation itself cannot be interrupted + on many platform APIs. This means that even when specifying a timeout, you are not + guaranteed to see a timeout exception until at least after however long process + creation takes. + +2. **Extremely Small Timeout Values**: Setting very small timeout values (such as a few + milliseconds) may result in almost immediate :exc:`TimeoutExpired` exceptions because + process creation and system scheduling inherently require time. + .. _converting-argument-sequence: Converting an argument sequence to a string on Windows |