chosen <a class="reference internal" href="../../glossary.html#term-backend-Prolog-compiler"><span class="xref std std-term">backend Prolog compiler</span></a>).</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>This directive requires a <a class="reference internal" href="../../glossary.html#term-backend-Prolog-compiler"><span class="xref std std-term">backend Prolog compiler</span></a> providing
compatible multi-threading primitives. The value of the read-only
<a class="reference i