osx man page for ualarm

UALARM(3)						   BSD Library Functions Manual 						 UALARM(3)

NAME
     ualarm -- schedule signal after specified time

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     useconds_t
     ualarm(useconds_t useconds, useconds_t interval);

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

     The ualarm() function waits a count of useconds before asserting the terminating signal SIGALRM.  System activity or time used in processing
     the call may cause a slight delay.

     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 useconds number of microseconds have passed).

     Due to a setitimer(2) restriction, the maximum number of useconds and interval is limited to 100,000,000,000,000 (in case this value fits in
     the unsigned integer).

RETURN VALUES
     When the signal has successfully been caught, ualarm() returns the amount of time left on the clock.

NOTES
     A microsecond is 0.000001 seconds.

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

HISTORY
     The ualarm() function appeared in 4.3BSD.

BSD
								  April 19, 1994							       BSD