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.