Make sleep(3) and usleep(3) more consistent and remove extraneous

historic implementation details that get in the way of readability.
Our usleep(3) does not return EINVAL for values >= 1,000,000 but
still mention it in CAVEATS since some do.
Portions adapted from FreeBSD.  OK jmc@

1 files changed, 15 insertions, 23 deletions

diff --git a/lib/libc/gen/sleep.3 b/lib/libc/gen/sleep.3
index de0d7974faf..a112aded241 100644
--- a/lib/libc/gen/sleep.3
+++ b/lib/libc/gen/sleep.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sleep.3,v 1.11 2008/10/24 14:34:39 jmc Exp $
+.\"	$OpenBSD: sleep.3,v 1.12 2012/10/16 18:35:40 millert Exp $
 .\"
 .\" Copyright (c) 1986, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -27,12 +27,12 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: October 24 2008 $
+.Dd $Mdocdate: October 16 2012 $
 .Dt SLEEP 3
 .Os
 .Sh NAME
 .Nm sleep
-.Nd suspend process execution for interval of seconds
+.Nd suspend process execution for interval measured in seconds
 .Sh SYNOPSIS
 .Fd #include <unistd.h>
 .Ft unsigned int
@@ -40,25 +40,23 @@
 .Sh DESCRIPTION
 The
 .Fn sleep
-function suspends execution of the calling process until either the
-number of seconds specified by
+function suspends execution of the calling process until either
 .Fa seconds
-have elapsed or a signal is delivered to the calling process and its
-action is to invoke a signal-catching function or to terminate the process.
+seconds have elapsed or a signal is delivered to the process and its
+action is to invoke a signal-catching function or to terminate the
+process.
 The suspension time may be longer than requested due to the
 scheduling of other activity by the system.
 .Pp
 This function is implemented using
-.Xr nanosleep 2 ;
-it requires one system call each time it is invoked.
-A similar but less compatible function can be obtained with a single
-.Xr select 2 ;
-such a function would not restart after signals, and also does not interfere
-with other uses of
-.Xr setitimer 2
-(not that
-.Fn sleep
-interferes with interval timers anymore).
+.Xr nanosleep 2
+by pausing for
+.Fa seconds
+seconds or until a signal occurs.
+Consequently, in this implementation,
+sleeping has no effect on the state of process timers,
+and there is no special handling for
+.Dv SIGALRM .
 .Sh RETURN VALUES
 If the
 .Fn sleep
@@ -72,12 +70,6 @@ slept) in seconds.
 .Sh SEE ALSO
 .Xr sleep 1 ,
 .Xr nanosleep 2 ,
-.Xr select 2 ,
-.Xr setitimer 2 ,
-.Xr sigaction 2 ,
-.Xr sigsuspend 2 ,
-.Xr alarm 3 ,
-.Xr pause 3 ,
 .Xr usleep 3
 .Sh STANDARDS
 The