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<h1><span class="section-number">11.5. </span>Calling fork(), system(), or popen() in MPI processes<a class="headerlink" href="#calling-fork-system-or-popen-in-mpi-processes" title="Permalink to this heading"></a></h1>
<p>It may be possible to call <code class="docutils literal notranslate"><span class="pre">fork()</span></code>, <code class="docutils literal notranslate"><span class="pre">system()</span></code>, <code class="docutils literal notranslate"><span class="pre">popen()</span></code>, etc. calls
from an MPI process, but it depends on a lot of factors, including (but not
limited to):</p>
<ul class="simple">
<li><p>The operating system</p></li>
<li><p>The underlying compute hardware</p></li>
<li><p>The network stack</p></li>
<li><p>Interactions with other middleware in the MPI process</p></li>
</ul>
<p>Users are encouraged to avoid invoking these operations in their MPI applications
as they may cause issues with Open MPI’s operation or the operation of underlying
components, such as <a class="reference external" href="https://openucx.org/">UCX</a>
and <a class="reference external" href="https://libfabric.org/">Libfabric</a>.</p>
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