minix/lib/libc/sys/timer_settime.2
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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.\" $NetBSD: timer_settime.2,v 1.6 2010/05/17 07:22:03 jruoho Exp $
.\"
.\" Copyright (c) 2003 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Christos Zoulas.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd May 17, 2010
.Dt TIMER_SETTIME 2
.Os
.Sh NAME
.Nm timer_settime ,
.Nm timer_gettime ,
.Nm timer_getoverrun
.Nd process timer manipulation
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In time.h
.Ft int
.Fn timer_settime "timer_t timerid" "int flags" "const struct itimerspec * restrict tim" "struct itimerspec * restrict otim"
.Ft int
.Fn timer_gettime "timer_t timerid" "struct itimerspec *tim"
.Ft int
.Fn timer_getoverrun "timer_t timerid"
.Sh DESCRIPTION
The
.Fn timer_settime
sets the next expiration time of the timer with ID
.Ar timerid
to the
.Fa it_value
(see
.Xr itimerspec 3 )
specified in the
.Ar tim
argument.
If the value is 0, the timer is disarmed.
If the argument
.Ar otim
is not
.Dv NULL
the old timer settingas are returned.
.Pp
If the
.Ar flags
argument is set to
.Dv TIMER_RELTIME
then the expiration time is set to the value in nanoseconds specified
in the
.Ar tim
argument from the time the call to
.Fn timer_settime
was made.
If the
.Ar flags
argument is set to
.Dv TIMER_ABSTIME
then the expiration time is set to be equal to the difference between the
clock associated with this timer, and the value specified in the
.Ar tim
argument.
If that time has already passed, then the call succeeds, and the
expiration notification occurs.
.Pp
If the
.Fa it_interval
of the
.Ar tim
argument is non-zero, then the timer reloads upon expiration.
.Pp
The
.Fn timer_gettime
function returns the current settings of the timer
specified by the
.Ar timerid
argument in the
.Ar tim
argument.
.Pp
Only one notification event (signal) can be pending for a given timer
and process.
If a timer expires while the signal is still queued for delivery, then
the overrun counter for that timer is increased.
The counter can store values up to
.Dv DELAYTIMER_MAX .
When the signal is finally delivered to the process, then the
.Fn timer_getoverrun
function can be used to retrieve the overrun counter for the timer
specified in the
.Ar timerid
argument.
.Sh NOTES
Expiration time values are always rounded up to the resolution of the timer,
so a notification will never be sent before the requested time.
Values returned in the
.Ar otim
argument of
.Fn timer_settime
or in the
.Ar tim
argment of
.Fn timer_gettime
are subject to the above rounding effect and might not exactly match the
requested values by the user.
.Sh RETURN VALUES
If successful, the
.Fn timer_gettime
and
.Fn timer_settime
functions return 0, and the
.Fn timer_getoverrun
function returns the expiration overrun count for the specified timer.
Otherwise, the functions return \-1, and set
.Dv errno
to indicate the error.
.Sh ERRORS
The
.Fn timer_gettime ,
.Fn timer_getoverrun ,
and
.Fn timer_settime
functions will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The argument
.Ar timerid
does not correspond to a valid timer id as returned by
.Fn timer_create
or that timer id has been deleted by
.Fn timer_delete .
.El
.Pp
The
.Fn timer_settime
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
A nanosecond field in the
.Ar tim
structure specified a value less than zero or greater than or equal to 10e9.
.El
.Sh SEE ALSO
.Xr clock_gettime 2 ,
.Xr timer_create 2 ,
.Xr timer_delete 2
.Sh STANDARDS
.St -p1003.1b-93 ,
.St -p1003.1i-95