ax with the form
    <code class="computeroutput">sig.<a class="link" href="../boost/signals2/signal.html#id-1_3_37_6_9_3_1_2_24_1-bb">connect</a>(slot)</code>, but a
    more terse syntax <code class="computeroutput">sig += slot</code> has been suggested (and
    has been used by other signals &amp; slots implementations). There
    are several reasons as to why this syntax has been
    rejected:</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p