described in the table below. If not specified, the default value
used will check for all 3 types of events.
-\begin{tableii}{l|l}{code}{Constant}{Meaning}
+\begin{tableii}{l|l}{constant}{Constant}{Meaning}
\lineii{POLLIN}{There is data to read}
\lineii{POLLPRI}{There is urgent data to read}
\lineii{POLLOUT}{Ready for output: writing will not block}
so forth.
An empty list indicates that the call timed out and no file
descriptors had any events to report.
+If \var{timeout} is given, it specifies the length of time in
+milliseconds which the system will wait for events before returning.
+If \var{timeout} is omitted, negative, or \code{None}, the call will
+block until there is an event for this poll object.
\end{methoddesc}