The
ualarm()
function causes the signal
SIGALRM
to be sent to the invoking process after (not less than)
usecs
microseconds.
The delay may be lengthened slightly by any system activity
or by the time spent processing the call or by the
granularity of system timers.
Unless caught or ignored, the
SIGALRM
signal will terminate the process.
If the
interval
argument is non-zero, further
SIGALRM
signals will be sent every
interval
microseconds after the first.
RETURN VALUE
This function returns the number of microseconds remaining for
any alarm that was previously set, or 0 if no alarm was pending.
ERRORS
EINTR
Interrupted by a signal.
EINVAL
usecs or interval is not smaller than 1000000.
(On systems where that is considered an error.)
CONFORMING TO
4.3BSD, POSIX.1-2001.
POSIX.1-2001 marks
ualarm()
as obsolete.
POSIX.1-2008 removes the specification of
ualarm().
4.3BSD, SUSv2, and POSIX do not define any errors.
NOTES
The type
useconds_t
is an unsigned integer type capable of holding integers
in the range [0,1000000].
On the original BSD implementation, and in glibc before version 2.1,
the arguments to
ualarm()
were instead typed as
unsigned int.
Programs will be more portable if they never mention
useconds_t
explicitly.
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
