1 .\" This manpage is Copyright (C) 1992 Drew Eckhardt;
2 .\" and Copyright (C) 1993 Michael Haardt, Ian Jackson.
4 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
6 .\" Modified Wed Jul 21 19:42:57 1993 by Rik Faith <faith@cs.unc.edu>
7 .\" Modified Sun Jul 21 21:25:26 1996 by Andries Brouwer <aeb@cwi.nl>
8 .\" Modified Wed Nov 6 03:46:05 1996 by Eric S. Raymond <esr@thyrsus.com>
10 .TH ALARM 2 2017-05-03 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
12 alarm \- set an alarm clock for delivery of a signal
15 .RI ( libc ", " \-lc )
18 .B #include <unistd.h>
20 .BI "unsigned int alarm(unsigned int " seconds );
26 signal to be delivered to the calling process in
32 is zero, any pending alarm is canceled.
34 In any event any previously set
39 returns the number of seconds remaining until any previously scheduled
40 alarm was due to be delivered, or zero if there was no previously
43 POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
48 share the same timer; calls to one will interfere with use of the
55 and are not inherited by children created via
59 may be implemented using
67 Scheduling delays can, as ever, cause the execution of the process to
68 be delayed by an arbitrary amount of time.
77 .BR timerfd_create (2),