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| -rw-r--r-- | docs/LanguageExtensions.html | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/docs/LanguageExtensions.html b/docs/LanguageExtensions.html index bdb04ac1a5..cbdebe12de 100644 --- a/docs/LanguageExtensions.html +++ b/docs/LanguageExtensions.html @@ -665,6 +665,12 @@ void f(void) __attribute__((availability(macosx,introduced=10.4,deprecated=10.6, <dd>Apple's Mac OS X operating system. The minimum deployment target is specified by the <code>-mmacosx-version-min=<i>version</i></code> command-line argument.</dd> </dl> +<p>A declaration can be used even when deploying back to a platform +version prior to when the declaration was introduced. When this +happens, the declaration is <a + href="https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WeakLinking.html">weakly +linked</a>, as if the <code>weak_import</code> attribute were added to the declaration. A weakly-linked declaration may or may not be present a run-time, and a program can determine whether the declaration is present by checking whether the address of that declaration is non-NULL.</p> + <!-- ======================================================================= --> <h2 id="checking_language_features">Checks for Standard Language Features</h2> <!-- ======================================================================= --> |