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<a name="Implementing-PARALLEL-construct"></a>
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Next: <a href="Implementing-FOR-construct.html#Implementing-FOR-construct" accesskey="n" rel="next">Implementing FOR construct</a>, Previous: <a href="Implementing-REDUCTION-clause.html#Implementing-REDUCTION-clause" accesskey="p" rel="prev">Implementing REDUCTION clause</a>, Up: <a href="The-libgomp-ABI.html#The-libgomp-ABI" accesskey="u" rel="up">The libgomp ABI</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html#Library-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Implementing-PARALLEL-construct-1"></a>
<h3 class="section">9.10 Implementing PARALLEL construct</h3>

<div class="smallexample">
<pre class="smallexample">  #pragma omp parallel
  {
    body;
  }
</pre></div>

<p>becomes
</p>
<div class="smallexample">
<pre class="smallexample">  void subfunction (void *data)
  {
    use data;
    body;
  }

  setup data;
  GOMP_parallel_start (subfunction, &amp;data, num_threads);
  subfunction (&amp;data);
  GOMP_parallel_end ();
</pre></div>

<div class="smallexample">
<pre class="smallexample">  void GOMP_parallel_start (void (*fn)(void *), void *data, unsigned num_threads)
</pre></div>

<p>The <var>FN</var> argument is the subfunction to be run in parallel.
</p>
<p>The <var>DATA</var> argument is a pointer to a structure used to 
communicate data in and out of the subfunction, as discussed
above with respect to FIRSTPRIVATE et al.
</p>
<p>The <var>NUM_THREADS</var> argument is 1 if an IF clause is present
and false, or the value of the NUM_THREADS clause, if
present, or 0.
</p>
<p>The function needs to create the appropriate number of
threads and/or launch them from the dock.  It needs to
create the team structure and assign team ids.
</p>
<div class="smallexample">
<pre class="smallexample">  void GOMP_parallel_end (void)
</pre></div>

<p>Tears down the team and returns us to the previous <code>omp_in_parallel()</code> state.
</p>


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