    <!-- return types: from API spec., p. 89, 6.13.6 Relational Functions; 
         and OpenCL C spec., p. 20, 9.4.5 Half - Relational Functions.
         These words apply to: isequal, isnotequal, isgreater, isgreaterequal, 
         isless, islessequal, islessgreater, isfinite, isinf, isnan, isnormal, 
         isordered, isunordered and signbit -->

    <para>
      The function returns a 0 if the specified relation is <constant>false</constant> and a 1
      if the specified relation is <constant>true</constant> for scalar argument types. These
      functions shall return a 0 if the specified relation is <constant>false</constant> and a -
      1 (i.e. all bits set) if the specified relation is <constant>true</constant> for vector
      argument types.
    </para>

<!-- 13-Dec-2013, rev. 19 -->