d`</code> is the process id
of the subprocess.</p>
<p>The stack trace of the error in subprocess can be printed via
<code>err$parent$trace</code>. By default the trace omits the boilerplate frames
added by callr, these are usually not very useful for the user.
Nevertheless they are still included in <code>err$parent$trace$calls</code>.</p>
<pre class="r"><code>err$parent$trace</code></pre>
<PRE class="fansi fansi-output"><CODE>#&gt; 
#&gt; <span style='font-weight: bold;'> ERROR TRACE for packageNotFoundErr