UALARM(3C) Standard C Library Functions UALARM(3C)
NAME
ualarm - schedule signal after interval in microseconds
SYNOPSIS
#include <unistd.h> useconds_t ualarm(
useconds_t useconds,
useconds_t interval);
DESCRIPTION
The
ualarm() function causes the SIGALRM signal to be generated for the
calling process after the number of real-time microseconds specified by
the
useconds argument has elapsed. When the
interval argument is non-
zero, repeated timeout notification occurs with a period in
microseconds specified by the
interval argument. If the notification
signal, SIGALRM, is not caught or ignored, the calling process is
terminated.
Because of scheduling delays, resumption of execution when the signal
is caught may be delayed an arbitrary amount of time.
Interactions between
ualarm() and either
alarm(2) or
sleep(3C) are
unspecified.
RETURN VALUES
The
ualarm() function returns the number of microseconds remaining from
the previous
ualarm() call. If no timeouts are pending or if
ualarm()
has not previously been called,
ualarm() returns 0.
ERRORS
No errors are defined.
USAGE
The
ualarm() function is a simplified interface to
setitimer(2), and
uses the ITIMER_REAL interval timer. It's use has been deprecated in
favor of the
timer_create(3C) family of functions.
INTERFACE STABILITY
Obsolete Standard.
SEE ALSO
alarm(2),
setitimer(2),
sighold(3C),
signal(3C),
sleep(3C),
timer_create(3C),
usleep(3C),
unistd.h(3HEAD),
standards(7)STANDARDS
The
ualarm() function is available in the following compilation
environments. See
standards(7).
+o X/Open Portability Guide Issue 4, Version 2 ("XPG4.2")
+o Version 2 of the Single UNIX Specification ("SUSv2")
+o Version 3 of the Single UNIX Specification ("SUSv3")
It is marked obsolete in Version 3 of the Single UNIX Specification
("SUSv3"), and was removed from IEEE Std 1003.1-2008 ("POSIX.1").
illumos August 16, 2014 illumos
