diff options
Diffstat (limited to 'Doc/library')
| -rw-r--r-- | Doc/library/os.rst | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/Doc/library/os.rst b/Doc/library/os.rst index 28921ad..86add0c 100644 --- a/Doc/library/os.rst +++ b/Doc/library/os.rst @@ -3280,16 +3280,22 @@ written in Python, such as a mail server's external command delivery program. subprocesses. -.. function:: register_at_fork(func, when) +.. function:: register_at_fork(*, before=None, after_in_parent=None, \ + after_in_child=None) - Register *func* as a function to be executed when a new child process - is forked. *when* is a string specifying at which point the function is - called and can take the following values: + Register callables to be executed when a new child process is forked + using :func:`os.fork` or similar process cloning APIs. + The parameters are optional and keyword-only. + Each specifies a different call point. - * *"before"* means the function is called before forking a child process; - * *"parent"* means the function is called from the parent process after - forking a child process; - * *"child"* means the function is called from the child process. + * *before* is a function called before forking a child process. + * *after_in_parent* is a function called from the parent process + after forking a child process. + * *after_in_child* is a function called from the child process. + + These calls are only made if control is expected to return to the + Python interpreter. A typical :mod:`subprocess` launch will not + trigger them as the child is not going to re-enter the interpreter. Functions registered for execution before forking are called in reverse registration order. Functions registered for execution @@ -3300,6 +3306,8 @@ written in Python, such as a mail server's external command delivery program. call those functions, unless it explicitly calls :c:func:`PyOS_BeforeFork`, :c:func:`PyOS_AfterFork_Parent` and :c:func:`PyOS_AfterFork_Child`. + There is no way to unregister a function. + Availability: Unix. .. versionadded:: 3.7 |