\begin{verbatim}OPERATION_NOT_ALLOWED()\end{verbatim}
\begin{center}\rule{10em}{0.1pt}\end{center}
+\subsubsection{PIF\_HANDLE\_INVALID}
+
+You gave an invalid PIF handle. The PIF may have recently been deleted.
+The handle parameter echoes the bad value given.
+
+\vspace{0.3cm}
+{\bf Signature:}
+\begin{verbatim}PIF_HANDLE_INVALID(handle)\end{verbatim}
+\begin{center}\rule{10em}{0.1pt}\end{center}
+
\subsubsection{PIF\_IS\_PHYSICAL}
You tried to destroy a PIF, but it represents an aspect of the physical
\begin{verbatim}PIF_IS_PHYSICAL(PIF)\end{verbatim}
\begin{center}\rule{10em}{0.1pt}\end{center}
+\subsubsection{PIF\_METRICS\_HANDLE\_INVALID}
+
+You gave an invalid PIF\_metrics handle. The PIF\_metrics may have
+recently been deleted. The handle parameter echoes the bad value given.
+
+\vspace{0.3cm}
+{\bf Signature:}
+\begin{verbatim}PIF_METRICS_HANDLE_INVALID(handle)\end{verbatim}
+\begin{center}\rule{10em}{0.1pt}\end{center}
+
\subsubsection{SESSION\_AUTHENTICATION\_FAILED}
The credentials given by the user are incorrect, so access has been denied,