UALARM(3C) Standard C Library Functions UALARM(3C)
ualarm - schedule signal after interval in microseconds
#include <unistd.h>
useconds_t
ualarm(useconds_t useconds, useconds_t interval);
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.
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.
No errors are defined.
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.
Obsolete Standard.
alarm(2), setitimer(2), sighold(3C), signal(3C), sleep(3C),
timer_create(3C), usleep(3C), unistd.h(3HEAD), standards(7)
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
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