Update documentation for keep_alive to match new implementation

PR #880 changed the implementation of keep_alive to avoid weak
references when the nurse is pybind11-registered, but the documentation
didn't get updated to match.
This commit is contained in:
Bruce Merry 2017-09-01 09:27:00 +02:00 committed by Dean Moldovan
parent 2fb4e9532e
commit b490b44e34

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@ -177,9 +177,10 @@ indices start at one, while zero refers to the return value. For methods, index
index ``2``. Arbitrarily many call policies can be specified. When a ``Nurse``
with value ``None`` is detected at runtime, the call policy does nothing.
This feature internally relies on the ability to create a *weak reference* to
the nurse object, which is permitted by all classes exposed via pybind11. When
the nurse object does not support weak references, an exception will be thrown.
When the nurse is not a pybind11-registered type, the implementation internally
relies on the ability to create a *weak reference* to the nurse object. When
the nurse object is not a pybind11-registered type and does not support weak
references, an exception will be thrown.
Consider the following example: here, the binding code for a list append
operation ties the lifetime of the newly added element to the underlying