-@deffnx {C Function} scm_setitimer (which_timer, interval_seconds, interval_microseconds, periodic_seconds, periodic_microseconds)
-Get or set the periods programmed in certain system timers. These
-timers have a current interval value which counts down and on reaching
-zero raises a signal. An optional periodic value can be set to
-restart from there each time, for periodic operation.
-@var{which_timer} is one of the following values
+@deffnx {C Function} scm_setitimer (which_timer, interval_seconds, interval_microseconds, value_seconds, value_microseconds)
+Get or set the periods programmed in certain system timers.
+
+These timers have two settings. The first setting, the interval, is the
+value at which the timer will be reset when the current timer expires.
+The second is the current value of the timer, indicating when the next
+expiry will be signalled.
+
+@var{which_timer} is one of the following values: