</p>

<ul>
<li> '<tt>b</tt>': <em>block</em> timeout.  Specifies the upper limit on
the amount  of time  LuaSocket can  be blocked  by the  operating system
while waiting for completion of any single I/O operation. This is the
default mode;</li>

<li> '<tt>t</tt>':  <em>total</em> timeout. Specifies the  upper limit on
the amount of  time LuaSocket can block a Lua  script before returning from
a call.</li>
</ul>

<p class=parameters>
The  <b><tt>nil</tt></b>  timeout  <tt>value</tt> allows  operations  to  