diff options
Diffstat (limited to 'Doc/library/contextlib.rst')
| -rw-r--r-- | Doc/library/contextlib.rst | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/Doc/library/contextlib.rst b/Doc/library/contextlib.rst index a35ea569c1..e8dc17fed3 100644 --- a/Doc/library/contextlib.rst +++ b/Doc/library/contextlib.rst @@ -54,8 +54,12 @@ Functions provided: the exception has been handled, and execution will resume with the statement immediately following the :keyword:`with` statement. - contextmanager uses :class:`ContextDecorator` so the context managers it - creates can be used as decorators as well as in :keyword:`with` statements. + :func:`contextmanager` uses :class:`ContextDecorator` so the context managers + it creates can be used as decorators as well as in :keyword:`with` statements. + When used as a decorator, a new generator instance is implicitly created on + each function call (this allows the otherwise "one-shot" context managers + created by :func:`contextmanager` to meet the requirement that context + managers support multiple invocations in order to be used as decorators). .. versionchanged:: 3.2 Use of :class:`ContextDecorator`. @@ -155,6 +159,12 @@ Functions provided: def __exit__(self, *exc): return False + .. note:: + As the decorated function must be able to be called multiple times, the + underlying context manager must support use in multiple :keyword:`with` + statements. If this is not the case, then the original construct with the + explicit :keyword:`with` statement inside the function should be used. + .. versionadded:: 3.2 |