-<p><li>File descriptors specified by the client and allowed according to the
-configuration language will be connected. Each file descriptor is
-opened for reading or writing. Communication is via pipes, one end of
-each pipe being open on the appropriate file descriptor in the service
-program (when it is invoked) and the other end being held by the
-client process, which will read and write files it opens on behalf of
-its caller or file descriptors it is passed by its caller.
-
-Data may be passed into the service through reading pipes and out of
-it through writing pipes. These pipes can remain open only until the
-service and client have terminated, or can be made to stay open after
-the client has terminated and (if the service program forks) the main
-service process has exited; the behaviour is controlled by options
-passed to the client by its caller.
-
-The caller can arrange that a writing pipe be connected to a pipe or
-similar object and cause attempts to write to that descriptor by the
-service to generate a <code>SIGPIPE</code> (or <code>EPIPE</code> if
-<code>SIGPIPE</code> is caught or ignored) in the service.
-
-Likewise, the service can close filedescriptors specified for reading,
-which will cause the corresponding filedescriptors passed by the
-caller to be closed, so that if these are pipes processes which write
-to them will receive <code>SIGPIPE</code> or <code>EPIPE</code>.
-
-<p><li>If <code>no-suppress-args</code> is set then arguments passed to the client
-by its caller will be passed on, verbatim, to the service.
-
-<p><li>Fatal signals and system call failures experienced by the client will
-result in the disconnection of the service from the client and
-possibly some of the communication file descriptors described above;
-if <code>disconnect-hup</code> is set then the service will also be sent a
-<code>SIGHUP</code>.
-
-<p><li>The value of the <code>LOGNAME</code> (or <code>USER</code>) environment variable
-as passed to the client will be used as the login name of the calling
-user if the uid of the calling process matches the uid corresponding
-to that login name. Otherwise the calling uid's password entry will
-be used to determine the calling user's login name.
-
-This login name and the calling uid are available in the configuration
-language in the <code>calling-user</code> parameter and are passed to the
-service program in environment variables <code>USERV_USER</code> and
-<code>USERV_UID</code>.
-
-The shell corresponding to that login name (according to the password
-entry) is available as in the configuration language's
-<code>calling-user-shell</code> parameter.
-
-If no relevant password entry can be found then no service will be
-invoked.