bsd man page for ualarm

UALARM(3)						     Library Functions Manual							 UALARM(3)

NAME
       ualarm - schedule signal after specified time

SYNOPSIS
       unsigned ualarm(value, interval)
       unsigned value;
       unsigned interval;

DESCRIPTION
       This is a simplified interface to setitimer(2).

       Ualarm  causes  signal SIGALRM, see signal(3C), to be sent to the invoking process in a number of microseconds given by the value argument.
       Unless caught or ignored, the signal terminates the process.

       If the interval argument is non-zero, the SIGALRM signal will be sent to the process every interval microseconds after  the  timer  expires
       (e.g. after value microseconds have passed).

       Because	of scheduling delays, resumption of execution of when the signal is caught may be delayed an arbitrary amount.	The longest speci-
       fiable delay time (on the vax) is 2147483647 microseconds.

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

SEE ALSO
       getitimer(2), setitimer(2), sigpause(2), sigvec(2), signal(3C), sleep(3), alarm(3), usleep(3)

NOTES  (PDP-11)
       On the PDP-11, setitimer(2) rounds the number of microseconds up to seconds resolution, therefore ualarm doesn't give you any more  resolu-
       tion than alarm(3).

4.3 Berkeley Distribution					  August 26, 1988							 UALARM(3)