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freebsd/lib/libc/gen/alarm.3
Mike Pritchard b4176c89f9 The previous change to alarm.3 to improve the wording
was still somewhat confusing and poorly worded.  So I took
the alarm.3 man page from NetBSD, which looked much
better all around.

Obtained from: NetBSD
1996-07-19 22:19:08 +00:00

92 lines
3.0 KiB
Groff

.\" Copyright (c) 1980, 1991, 1993, 1994
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.\" @(#)alarm.3 8.2 (Berkeley) 4/19/94
.\"
.Dd April 19, 1994
.Dt ALARM 3
.Os BSD 4
.Sh NAME
.Nm alarm
.Nd set signal timer alarm
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft unsigned int
.Fn alarm "unsigned int seconds"
.Sh DESCRIPTION
.Bf -symbolic
This interface is made obsolete by setitimer(2).
.Ef
.Pp
The
.Fn alarm
function sets a timer to deliver the signal
.Dv SIGALRM
to the calling process after the specified number of
.Fa seconds .
If an alarm has already been set with
.Fn alarm
but has not been delivered, another call to
.Fn alarm
will supersede the prior call.
The request
.Fn alarm "0"
voids the current
alarm and the signal SIGALRM will not be delivered. The maximum number of
.Ar seconds
allowed
is 2147483647.
.Pp
The return value of
.Fn alarm
is the amount of time left on the timer from a previous call to
.Fn alarm .
If no alarm is currently set, the return value is 0.
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr setitimer 2 ,
.Xr sigpause 2 ,
.Xr sigvec 3 ,
.Xr signal 3 ,
.Xr sleep 3 ,
.Xr ualarm 3 ,
.Xr usleep 3
.Sh STANDARDS
The
.Fn alarm
function conforms to
.St -p1003.1-90 .
.Sh HISTORY
An
.Fn alarm
function appeared in
.At v7 .