On Mar 11, 2012, at 1:45 AM, Jean-Daniel Dupas wrote:
> Just a question.
>
> For a function introduced in 10.7, what append if the deployment target is
> 10.6 ? Does clang use weak linking for this function ?
Yes, it does. I've updated the documentation in r152543.
- Doug
> Le 11 mars 2012 à 05:53, Douglas Gregor a écrit :
>
>> Author: dgregor
>> Date: Sat Mar 10 22:53:21 2012
>> New Revision: 152531
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=152531&view=rev
>> Log:
>> Document the availability attribute
>>
>> Modified:
>> cfe/trunk/docs/LanguageExtensions.html
>> cfe/trunk/lib/Parse/ParseDecl.cpp
>>
>> Modified: cfe/trunk/docs/LanguageExtensions.html
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LanguageExtensions.html?rev=152531&r1=152530&r2=152531&view=diff
>> ==============================================================================
>> --- cfe/trunk/docs/LanguageExtensions.html (original)
>> +++ cfe/trunk/docs/LanguageExtensions.html Sat Mar 10 22:53:21 2012
>> @@ -30,6 +30,7 @@
>> <li><a href="#vectors">Vectors and Extended Vectors</a></li>
>> <li><a href="#deprecated">Messages on <tt>deprecated</tt> and
>> <tt>unavailable</tt> attributes</a></li>
>> <li><a href="#attributes-on-enumerators">Attributes on enumerators</a></li>
>> +<li><a href="#availability">Availability attribute</a></li>
>> <li><a href="#checking_language_features">Checks for Standard Language
>> Features</a>
>> <ul>
>> <li><a href="#cxx_exceptions">C++ exceptions</a></li>
>> @@ -622,6 +623,49 @@
>> <p>Query for this feature with
>> <tt>__has_extension(enumerator_attributes)</tt>.</p>
>>
>> <!-- =======================================================================
>> -->
>> +<h2 id="availability">Availability attribute</h2
>> +<!--
>> ======================================================================= -->
>> +
>> +<p>Clang introduces the <code>availability</code> attribute, which can
>> +be placed on declarations to describe the lifecycle of that
>> +declaration relative to operating system versions. Consider the function
>> declaration for a hypothetical function <code>f</code>:</p>
>> +
>> +<pre>
>> +void f(void)
>> __attribute__((availability(macosx,introduced=10.4,deprecated=10.6,obsoleted=10.7)));
>> +</pre>
>> +
>> +<p>The availability attribute states that <code>f</code> was introduced in
>> Mac OS X 10.4, deprecated in Mac OS X 10.6, and obsoleted in Mac OS X 10.7.
>> This information is used by Clang to determine when it is safe to use
>> <code>f</code>: for example, if Clang is instructed to compile code for Mac
>> OS X 10.5, a call to <code>f()</code> succeeds. If Clang is instructed to
>> compile code for Mac OS X 10.6, the call succeeds but Clang emits a warning
>> specifying that the function is deprecated. Finally, if Clang is instructed
>> to compile code for Mac OS X 10.7, the call fails because <code>f()</code>
>> is no longer available.</p>
>> +
>> +<p>The availablility attribute is a comma-separated list starting with the
>> platform name and then including clauses specifying important milestones in
>> the declaration's lifetime (in any order) along with additional information.
>> Those clauses can be:</p>
>> +
>> +<dl>
>> + <dt>introduced=<i>version</i></dt>
>> + <dd>The first version in which this declaration was introduced.</dd>
>> +
>> + <dt>deprecated=<i>version</i></dt>
>> + <dd>The first version in which this declaration was deprecated, meaning
>> that users should migrate away from this API.</dd>
>> +
>> + <dt>obsoleted=<i>version</i></dt>
>> + <dd>The first version in which this declaration was obsoleted, meaning
>> that it was removed completely and can no longer be used.</dd>
>> +
>> + <dt>unavailable</dt>
>> + <dd>This declaration is never available on this platform.</dd>
>> +
>> + <dt>message=<i>string-literal</i></dt>
>> + <dd>Additional message text that Clang will provide when emitting a
>> warning or error about use of a deprecated or obsoleted declaration. Useful
>> to direct users to replacement APIs.</dd>
>> +</dl>
>> +
>> +<p>Multiple availability attributes can be placed on a declaration, which
>> may correspond to different platforms. Only the availability attribute with
>> the platform corresponding to the target platform will be used; any others
>> will be ignored. If no availability attribute specifies availability for the
>> current target platform, the availability attributes are ignored. Supported
>> platforms are:</p>
>> +
>> +<dl>
>> + <dt>ios</dt>
>> + <dd>Apple's iOS operating system. The minimum deployment target is
>> specified by the <code>-mios-version-min=<i>version</i></code> or
>> <code>-miphoneos-version-min=<i>version</i></code> command-line
>> arguments.</dd>
>> +
>> + <dt>macosx</dt>
>> + <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>
>> +
>> +<!--
>> ======================================================================= -->
>> <h2 id="checking_language_features">Checks for Standard Language
>> Features</h2>
>> <!-- =======================================================================
>> -->
>>
>>
>> Modified: cfe/trunk/lib/Parse/ParseDecl.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDecl.cpp?rev=152531&r1=152530&r2=152531&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Parse/ParseDecl.cpp (original)
>> +++ cfe/trunk/lib/Parse/ParseDecl.cpp Sat Mar 10 22:53:21 2012
>> @@ -536,7 +536,7 @@
>> /// version-arg:
>> /// 'introduced' '=' version
>> /// 'deprecated' '=' version
>> -/// 'removed' = version
>> +/// 'obsoleted' = version
>> /// 'unavailable'
>> /// opt-message:
>> /// 'message' '=' <string>
>>
>>
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>
> -- Jean-Daniel
>
>
>
>
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