NAME

alarm − schedule signal after specified time

SYNOPSIS

alarm(seconds)
unsigned seconds;

DESCRIPTION

Alarm causes signal SIGALRM, see signal(2), to be sent to the invoking process in a number of seconds given by the argument. Unless caught or ignored, the signal terminates the process.

Alarm requests are not stacked; successive calls reset the alarm clock.  If the argument is 0, any alarm request is canceled.  Because the clock has a 1-second resolution, the signal may occur up to one second early; because of scheduling delays, resumption of execution of when the signal is caught may be delayed an arbitrary amount.  The longest specifiable delay time is 4,294,967,295 (2**32-1) seconds, or 136 years. 

The return value is the amount of time previously remaining in the alarm clock. 

SEE ALSO

pause(2), signal(2), sleep(3)

7th Edition