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Diffstat (limited to 'docs/AutomaticReferenceCounting.rst')
| -rw-r--r-- | docs/AutomaticReferenceCounting.rst | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/AutomaticReferenceCounting.rst b/docs/AutomaticReferenceCounting.rst index 1457b60..2faed23 100644 --- a/docs/AutomaticReferenceCounting.rst +++ b/docs/AutomaticReferenceCounting.rst @@ -594,7 +594,9 @@ retainable pointer type <arc.misc.c-retainable>` and it is: * a message send, and the declared method either has the ``cf_returns_not_retained`` attribute or it has neither the ``cf_returns_retained`` attribute nor a :ref:`selector family - <arc.method-families>` that implies a retained result. + <arc.method-families>` that implies a retained result, or +* :when-revised:`[beginning LLVM 3.6]` :revision:`a load from a` ``const`` + :revision:`non-system global variable.` An expression is :arc-term:`known retained` if it is an rvalue of :ref:`C retainable pointer type <arc.misc.c-retainable>` and it is: @@ -631,6 +633,12 @@ retain-agnostic, the conversion is treated as a ``__bridge`` cast. to an ObjC-typed local, and then calling ``CFRelease`` when done --- are a bit too likely to be accidentally accepted, leading to mysterious behavior. + For loads from ``const`` global variables of :ref:`C retainable pointer type + <arc.misc.c-retainable>`, it is reasonable to assume that global system + constants were initialitzed with true constants (e.g. string literals), but + user constants might have been initialized with something dynamically + allocated, using a global initializer. + .. _arc.objects.restrictions.conversion-exception-contextual: Conversion from retainable object pointer type in certain contexts |
