diff options
Diffstat (limited to 'Doc/c-api')
| -rw-r--r-- | Doc/c-api/exceptions.rst | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst index c7252ed..fd7aee7 100644 --- a/Doc/c-api/exceptions.rst +++ b/Doc/c-api/exceptions.rst @@ -421,17 +421,24 @@ Exception Objects .. c:function:: PyObject* PyException_GetCause(PyObject *ex) - Return the cause (another exception instance set by ``raise ... from ...``) - associated with the exception as a new reference, as accessible from Python - through :attr:`__cause__`. If there is no cause associated, this returns - *NULL*. + Return the cause (either an exception instance, or :const:`None`, + set by ``raise ... from ...``) associated with the exception as a new + reference, as accessible from Python through :attr:`__cause__`. + + If there is no cause associated, this returns *NULL* (from Python + ``__cause__ is Ellipsis``). If the cause is :const:`None`, the default + exception display routines stop showing the context chain. .. c:function:: void PyException_SetCause(PyObject *ex, PyObject *ctx) Set the cause associated with the exception to *ctx*. Use *NULL* to clear - it. There is no type check to make sure that *ctx* is an exception instance. - This steals a reference to *ctx*. + it. There is no type check to make sure that *ctx* is either an exception + instance or :const:`None`. This steals a reference to *ctx*. + + If the cause is set to :const:`None` the default exception display + routines will not display this exception's context, and will not follow the + chain any further. .. _unicodeexceptions: |