ess_status
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;waitpid&nbsp;:&nbsp;<span class="constructor">Unix</span>.wait_flag&nbsp;list&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;int&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;int&nbsp;*&nbsp;<span class="constructor">Unix</span>.process_status
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;system&nbsp;:&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">Unix</span>.process_status
&nbsp;&nbsp;<span class=