(timer-inc-time): Doc fix.

diff --git a/lisp/timer.el b/lisp/timer.el
index 0ca97ca3aeccd76700cb69838096c20d11603ebb..3131fe3c175deeb9c0ed39bd1ec229958bbfc3bd 100644 (file)
--- a/lisp/timer.el
+++ b/lisp/timer.el
@@ -127,7 +127,7 @@ SECS may be a fraction."
 
 (defun timer-inc-time (timer secs &optional usecs)
   "Increment the time set in TIMER by SECS seconds and USECS microseconds.
-SECS may be a fraction."
+SECS may be a fraction.  If USECS is omitted, that means it is zero."
   (let ((time (timer-relative-time
               (list (aref timer 1) (aref timer 2) (aref timer 3))
               secs