1ALARM(2)                   Linux Programmer's Manual                  ALARM(2)
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NAME

6       alarm - set an alarm clock for delivery of a signal
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SYNOPSIS

9       #include <unistd.h>
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11       unsigned int alarm(unsigned int seconds);
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DESCRIPTION

14       alarm() arranges for a SIGALRM signal to be delivered to the process in
15       seconds seconds.
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17       If seconds is zero, no new alarm() is scheduled.
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19       In any event any previously set alarm() is cancelled.
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RETURN VALUE

22       alarm() returns the number of seconds remaining  until  any  previously
23       scheduled alarm was due to be delivered, or zero if there was no previ‐
24       ously scheduled alarm.
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NOTES

27       alarm() and setitimer() share the same timer; calls to one will  inter‐
28       fere with use of the other.
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30       sleep()  may  be implemented using SIGALRM; mixing calls to alarm() and
31       sleep() is a bad idea.
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33       Scheduling delays can, as ever, cause the execution of the  process  to
34       be delayed by an arbitrary amount of time.
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CONFORMING TO

37       SVr4, POSIX.1-2001, 4.3BSD
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SEE ALSO

40       gettimeofday(2),  pause(2), select(2), setitimer(2), sigaction(2), sig‐
41       nal(2), sleep(3), time(7)
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45Linux                             1993-07-21                          ALARM(2)