		<dd>
				The subtrahend of the operation.&nbsp;
				Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>.
			</dd>
		</dl>
	<h4>Remarks</h4>
		<div>
			If the difference between <i>x</i> and <i>y</i> is less than <i>0</i>, the result is saturated to <i>0</i>.
		</div>
		<div>
			Previously, this macro could not be used inside <b>BOOST_PP_WHILE</b>.&nbsp;
			There is no longer any such restriction.&nbsp;
			It is more efficient, however, to use <b>BOOST_PP_SUB_D</b> in such a situation.
		</div>
	