sp;val&nbsp;join&nbsp;:&nbsp;Thread.t&nbsp;-&gt;&nbsp;unit
&nbsp;&nbsp;val&nbsp;yield&nbsp;:&nbsp;unit&nbsp;-&gt;&nbsp;unit
&nbsp;&nbsp;val&nbsp;wait_timed_read&nbsp;:&nbsp;Unix.file_descr&nbsp;-&gt;&nbsp;float&nbsp;-&gt;&nbsp;bool
&nbsp;&nbsp;val&nbsp;wait_timed_write&nbsp;:&nbsp;Unix.file_descr&nbsp;-&gt;&nbsp;float&nbsp;-&gt;&nbsp;bool
&nbsp;&nbsp;val&nbsp;select&nbsp;:
&nbsp;&nbsp;&nbsp;&nbsp;Unix.file_descr&nbsp;list&nbsp;-&gt;
&nbsp;&nbsp;&nbsp;&nbsp;Unix.file_descr&nbsp;list&nbsp;-&gt;
&nbsp;&nbsp;&n