and this should never happen.
Please use the regular functions of the fpu module for computations. 
For example prefer:
<p>

let a = fdiv_high 1. 3.;;
<p>

PS: The Interval module and the fpu module functions correctly set and 
restore the rounding mode 
for all interval computations, so you don't really need these functions.
<p>

PPS: Please, don't use them...<br>

<pre><span id="VALset_low"><span class="keyword">val</span> set_low</span> : <code class="type">unit -> unit</code></pre><div class="info ">
Se