\subsection{on}
\label{labon}
\noindent Name: \textbf{on}\\
\phantom{aaa}special value for certain global variables.\\[0.2cm]
\noindent Library names:\\
\verb|   sollya_obj_t sollya_lib_on()|\\
\verb|   int sollya_lib_is_on(sollya_obj_t)|\\[0.2cm]
\noindent Description: \begin{itemize}

\item \textbf{on} is a special value used to activate certain functionnalities 
   of \sollya.

\item As any value it can be affected to a variable and stored in lists.
\end{itemize}
\noindent Example 1: 
\begin{center}\begin{minipage}{15cm}\begin{Verbatim}[frame=single]
> p=1+x+x^2;
> mode=on;
> p;
1 + x * (1 + x)
> canonical=mode;
Canonical automatic printing output has been activated.
> p;
1 + x + x^2
\end{Verbatim}
\end{minipage}\end{center}
See also: \textbf{off} (\ref{laboff}), \textbf{autosimplify} (\ref{labautosimplify}), \textbf{canonical} (\ref{labcanonical}), \textbf{timing} (\ref{labtiming}), \textbf{fullparentheses} (\ref{labfullparentheses}), \textbf{midpointmode} (\ref{labmidpointmode}), \textbf{rationalmode} (\ref{labrationalmode}), \textbf{roundingwarnings} (\ref{labroundingwarnings}), \textbf{timing} (\ref{labtiming}), \textbf{dieonerrormode} (\ref{labdieonerrormode})
