UALARM(3) Library Functions Manual UALARM(3)
NAME
ualarmschedule signal after specified time
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
useconds_t
ualarm(useconds_t microseconds, useconds_t interval);
DESCRIPTION
This is a simplified interface to setitimer(2).
 
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
STANDARDS
The ualarm() functions conforms to X/Open Portability Guide Issue 4.2 (“XPG4.2”) and IEEE Std 1003.1-2001 (“POSIX.1”). The latter standard marked ualarm() as obsolescent and a later revision, IEEE Std 1003.1-2008 (“POSIX.1”), removed the specification of ualarm().
HISTORY
The ualarm() function appeared in 4.3BSD.