There is no special handling for SIGALRM as

sleep(3) is implemented using nanosleep(2).

bin/sleep/sleep.1

@@ -33,7 +33,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"	@(#)sleep.1	8.3 (Berkeley) 4/18/94
-.\"	$Id: sleep.1,v 1.8 1998/05/18 06:46:11 charnier Exp $
+.\"	$Id: sleep.1,v 1.9 1999/05/08 10:22:02 kris Exp $
 .\"
 .Dd April 18, 1994
 .Dt SLEEP 1
@@ -54,21 +54,13 @@ suspends execution for a minimum of
 is used to schedule the execution of other commands (see
 .Sx EXAMPLES
 below).
-.Pp
-If the
-.Nm
-command
-receives a SIGALRM signal, it terminates normally with a zero exit status,
-for any other signal it takes the standard action.
 .Sh DIAGNOSTICS
 The
 .Nm
 utility exits with one of the following values:
 .Bl -tag -width flag
 .It Li \&0
-On successful completion, or if the signal
-.Dv SIGALRM
-was received.
+On successful completion.
 .It Li \&>\&0
 An error occurred.
 .El
@@ -112,7 +104,7 @@ is done courteously by sleeping for 70 seconds in between each
 awk job.
 .Sh SEE ALSO
 .Xr at 1 ,
-.Xr setitimer 2 ,
+.Xr nanosleep 2 ,
 .Xr alarm 3 ,
 .Xr sleep 3
 .Sh STANDARDS