NAME
ualarm —
schedule signal after
specified time
LIBRARY
Standard C Library (libc, -lc)
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.