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<a name="ISO_002fIEC-14882_003a1998-Edits-for-Thread_002dLocal-Storage"></a>
<h4 class="subsection">6.64.2 ISO/IEC 14882:1998 Edits for Thread-Local Storage</h4>

<p>The following are a set of changes to ISO/IEC 14882:1998 (aka C++98)
that document the exact semantics of the language extension.
</p>
<ul>
<li> <b>[intro.execution]</b>

<p>New text after paragraph 4
</p>
<blockquote>
<p>A <em>thread</em> is a flow of control within the abstract machine.
It is implementation defined whether or not there may be more than
one thread.
</p></blockquote>

<p>New text after paragraph 7
</p>
<blockquote>
<p>It is unspecified whether additional action must be taken to
ensure when and whether side effects are visible to other threads.
</p></blockquote>

</li><li> <b>[lex.key]</b>

<p>Add <code>__thread</code>.
</p>
</li><li> <b>[basic.start.main]</b>

<p>Add after paragraph 5
</p>
<blockquote>
<p>The thread that begins execution at the <code>main</code> function is called
the <em>main thread</em>.  It is implementation defined how functions
beginning threads other than the main thread are designated or typed.
A function so designated, as well as the <code>main</code> function, is called
a <em>thread startup function</em>.  It is implementation defined what
happens if a thread startup function returns.  It is implementation
defined what happens to other threads when any thread calls <code>exit</code>.
</p></blockquote>

</li><li> <b>[basic.start.init]</b>

<p>Add after paragraph 4
</p>
<blockquote>
<p>The storage for an object of thread storage duration shall be
statically initialized before the first statement of the thread startup
function.  An object of thread storage duration shall not require
dynamic initialization.
</p></blockquote>

</li><li> <b>[basic.start.term]</b>

<p>Add after paragraph 3
</p>
<blockquote>
<p>The type of an object with thread storage duration shall not have a
non-trivial destructor, nor shall it be an array type whose elements
(directly or indirectly) have non-trivial destructors.
</p></blockquote>

</li><li> <b>[basic.stc]</b>

<p>Add &ldquo;thread storage duration&rdquo; to the list in paragraph 1.
</p>
<p>Change paragraph 2
</p>
<blockquote>
<p>Thread, static, and automatic storage durations are associated with
objects introduced by declarations [&hellip;].
</p></blockquote>

<p>Add <code>__thread</code> to the list of specifiers in paragraph 3.
</p>
</li><li> <b>[basic.stc.thread]</b>

<p>New section before <b>[basic.stc.static]</b>
</p>
<blockquote>
<p>The keyword <code>__thread</code> applied to a non-local object gives the
object thread storage duration.
</p>
<p>A local variable or class data member declared both <code>static</code>
and <code>__thread</code> gives the variable or member thread storage
duration.
</p></blockquote>

</li><li> <b>[basic.stc.static]</b>

<p>Change paragraph 1
</p>
<blockquote>
<p>All objects that have neither thread storage duration, dynamic
storage duration nor are local [&hellip;].
</p></blockquote>

</li><li> <b>[dcl.stc]</b>

<p>Add <code>__thread</code> to the list in paragraph 1.
</p>
<p>Change paragraph 1
</p>
<blockquote>
<p>With the exception of <code>__thread</code>, at most one
<var>storage-class-specifier</var> shall appear in a given
<var>decl-specifier-seq</var>.  The <code>__thread</code> specifier may
be used alone, or immediately following the <code>extern</code> or
<code>static</code> specifiers.  [&hellip;]
</p></blockquote>

<p>Add after paragraph 5
</p>
<blockquote>
<p>The <code>__thread</code> specifier can be applied only to the names of objects
and to anonymous unions.
</p></blockquote>

</li><li> <b>[class.mem]</b>

<p>Add after paragraph 6
</p>
<blockquote>
<p>Non-<code>static</code> members shall not be <code>__thread</code>.
</p></blockquote>
</li></ul>

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