| UALARM(3) | Library Functions Manual | UALARM(3) |
ualarm — schedule
signal after specified time
Standard C Library (libc, -lc)
#include
<unistd.h>
useconds_t
ualarm(useconds_t useconds,
useconds_t interval);
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).
When the signal has successfully been caught,
ualarm() returns the amount of time left on the
clock.
A microsecond is 0.000001 seconds.
getitimer(2), setitimer(2), sigpause(2), sigvec(2), alarm(3), signal(3), sleep(3), usleep(3)
The ualarm() function appeared in
4.3BSD.
| April 19, 1994 | macOS 15.0 |