-0 if the new element was already a member of the set
--2 if the key contains a non set value
-</pre><h2><a name="See also">See also</a></h2>
-<ul><li> <a href="SremCommand.html">SREM</a></li><li> <a href="SismemberCommand.html">SISMEMBER</a></li><li> <a href="ScardCommand.html">SCARD</a></li><li> <a href="SmembersCommand.html">SMEMBERS</a></li><li> <a href="SinterCommand.html">SINTER</a></li><li> <a href="SinterstoreCommand.html">SINTERSTORE</a></li></ul>