-This option prints on stdout the time at which the screensaver last activated
-(blanked the screen) or deactivated (restored the screen.) Note that the
-activation-time is not the last time at which the user was active, but is
-some time later (it is the time at which either: xscreensaver decided that
-the user has been idle long enough; or, the user explicitly activated the
-screensaver or locker.)
+Prints the time at which the screensaver last activated or
+deactivated (roughly, how long the user has been idle or non-idle: but
+not quite, since it only tells you when the screen became blanked or
+un-blanked.)
+.SH DIAGNOSTICS
+If an error occurs while communicating with the \fIxscreensaver\fP daemon, or
+if the daemon reports an error, a diagnostic message will be printed to
+stderr, and \fIxscreensaver-command\fP will exit with a non-zero value. If
+the command is accepted, an indication of this will be printed to stdout, and
+the exit value will be zero.