2fe8fb192f
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
193 lines
5 KiB
Groff
193 lines
5 KiB
Groff
.\" $NetBSD: getitimer.2,v 1.24 2010/04/30 04:17:45 jruoho Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" 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.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
|
|
.\"
|
|
.\" @(#)getitimer.2 8.3 (Berkeley) 5/16/95
|
|
.\"
|
|
.Dd April 30, 2010
|
|
.Dt GETITIMER 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm getitimer ,
|
|
.Nm setitimer
|
|
.Nd get/set value of interval timer
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/time.h
|
|
.Fd #define ITIMER_REAL 0
|
|
.Fd #define ITIMER_VIRTUAL 1
|
|
.Fd #define ITIMER_PROF 2
|
|
.Ft int
|
|
.Fn getitimer "int which" "struct itimerval *value"
|
|
.Ft int
|
|
.Fn setitimer "int which" "const struct itimerval * restrict value" "struct itimerval * restrict ovalue"
|
|
.Sh DESCRIPTION
|
|
The system provides each process with three interval timers,
|
|
defined in
|
|
.Ao Pa sys/time.h Ac .
|
|
The
|
|
.Fn getitimer
|
|
call returns the current value for the timer specified in
|
|
.Fa which
|
|
in the structure at
|
|
.Fa value .
|
|
The
|
|
.Fn setitimer
|
|
call sets a timer to the specified
|
|
.Fa value
|
|
(returning the previous value of the timer if
|
|
.Fa ovalue
|
|
is non-nil).
|
|
.Pp
|
|
A timer value is defined by the
|
|
.Fa itimerval
|
|
structure:
|
|
.Bd -literal -offset indent
|
|
struct itimerval {
|
|
struct timeval it_interval; /* timer interval */
|
|
struct timeval it_value; /* current value */
|
|
};
|
|
.Ed
|
|
.Pp
|
|
If
|
|
.Fa it_value
|
|
is non-zero, it indicates the time to the next timer expiration.
|
|
If
|
|
.Fa it_interval
|
|
is non-zero, it specifies a value to be used in reloading
|
|
.Fa it_value
|
|
when the timer expires.
|
|
Setting
|
|
.Fa it_value
|
|
to 0 disables a timer.
|
|
Setting
|
|
.Fa it_interval
|
|
to 0 causes a timer to be disabled after its next expiration (assuming
|
|
.Fa it_value
|
|
is non-zero).
|
|
.Pp
|
|
Time values smaller than the resolution of the
|
|
system clock are rounded up to this resolution
|
|
(typically 10 milliseconds).
|
|
.Pp
|
|
The
|
|
.Dv ITIMER_REAL
|
|
timer decrements in real time.
|
|
A
|
|
.Dv SIGALRM
|
|
signal is
|
|
delivered when this timer expires.
|
|
.Pp
|
|
The
|
|
.Dv ITIMER_VIRTUAL
|
|
timer decrements in process virtual time.
|
|
It runs only when the process is executing.
|
|
A
|
|
.Dv SIGVTALRM
|
|
signal
|
|
is delivered when it expires.
|
|
.Pp
|
|
The
|
|
.Dv ITIMER_PROF
|
|
timer decrements both in process virtual time and
|
|
when the system is running on behalf of the process.
|
|
It is designed to be used by interpreters in statistically profiling
|
|
the execution of interpreted programs.
|
|
Each time the
|
|
.Dv ITIMER_PROF
|
|
timer expires, the
|
|
.Dv SIGPROF
|
|
signal is
|
|
delivered.
|
|
Because this signal may interrupt in-progress
|
|
system calls, programs using this timer must be prepared to
|
|
restart interrupted system calls.
|
|
.Sh NOTES
|
|
Macros for manipulating time values are defined in the
|
|
.In sys/time.h
|
|
header;
|
|
.Fn timerclear
|
|
sets a time value to zero,
|
|
.Fn timerisset
|
|
tests if a time value is non-zero,
|
|
.Fn timercmp
|
|
compares two time values,
|
|
.Fn timeradd
|
|
adds a time value to another time value,
|
|
.Fn timersub
|
|
computes the time difference between two time values.
|
|
For additional details, see
|
|
.Xr timeradd 3 .
|
|
.Sh RETURN VALUES
|
|
If the calls succeed, a value of 0 is returned.
|
|
If an error occurs, the value \-1 is returned, and a more precise error
|
|
code is placed in the global variable
|
|
.Va errno .
|
|
.Sh ERRORS
|
|
.Fn getitimer
|
|
and
|
|
.Fn setitimer
|
|
will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa value
|
|
parameter specified a bad address.
|
|
.It Bq Er EINVAL
|
|
A
|
|
.Fa value
|
|
parameter specified a time that was too large
|
|
to be handled.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr gettimeofday 2 ,
|
|
.Xr poll 2 ,
|
|
.Xr select 2 ,
|
|
.Xr sigaction 2
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn getitimer
|
|
and
|
|
.Fn setitimer
|
|
functions conform to
|
|
.St -p1003.1-2001 .
|
|
The later
|
|
.St -p1003.1-2008
|
|
revision however marked both functions as obsolescent,
|
|
recommending the use of
|
|
.Xr timer_gettime 2
|
|
and
|
|
.Xr timer_settime 2
|
|
instead.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn getitimer
|
|
function call appeared in
|
|
.Bx 4.2 .
|