
          XERBLA.

</PRE>
<B>Error Indicator</B>
<PRE>
  INFO    INTEGER
          = 0:  successful exit;
          &lt; 0:  if INFO = -i, the i-th argument had an illegal
                value;
          = 1:  if the Lyapunov equation is (nearly) singular
                (warning indicator);
                if DICO = 'C' this means that while the matrix A
                (or the factor S) has computed eigenvalues with
                negative real parts, it is only just stable in the
                sense