NAME
ualarm —
schedule signal after specified
time
LIBRARY
library “libc”
SYNOPSIS
#include
<unistd.h>
useconds_t
ualarm(useconds_t
microseconds, useconds_t
interval);
DESCRIPTION
The
ualarm()
function waits a count of microseconds 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 microseconds microseconds have passed).
RETURN VALUES
When the signal has successfully been caught,
ualarm() returns the amount of time left on the
clock. The maximum number of microseconds allowed is
2147483647. If there is an error setting the timer,
ualarm() returns ((useconds_t) -1).
SEE ALSO
getitimer(2), setitimer(2), sigaction(2), sigsuspend(2), alarm(3), signal(3), sigvec(3), sleep(3), usleep(3)
STANDARDS
The ualarm() function conforms to
IEEE Std 1003.1-2001 (“POSIX.1”).
However, the later IEEE Std 1003.1-2008
(“POSIX.1”) revision removed the function from the
specification.
HISTORY
The ualarm() function appeared in
4.3BSD.