.\" $NetBSD: timeradd.3,v 1.8 2010/06/07 18:40:16 jruoho Exp $
.\"
.\" Copyright (c) 2009 Jukka Ruohonen <jruohonen@iki.fi>
.\" Copyright (c) 1999 Kelly Yancey <kbyanc@posi.net>
.\" 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 author nor the names of any co-contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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.
.\"
.\" $FreeBSD: src/share/man/man3/timeradd.3,v 1.3 2003/09/08 19:57:19 ru Exp $
.\"
.Dd June 7, 2010
.Dt TIMERADD 3
.Os
.Sh NAME
.Nm timeradd
.Nd operations on time structure
.Sh SYNOPSIS
.In sys/time.h
.Ft void
.Fn timeradd "struct timeval *a" "struct timeval *b" "struct timeval *res"
.Ft void
.Fn timersub "struct timeval *a" "struct timeval *b" "struct timeval *res"
.Ft void
.Fn timerclear "struct timeval *tv"
.Ft int
.Fn timerisset "struct timeval *tv"
.Ft int
.Fn timercmp "struct timeval *a" "struct timeval *b" CMP
.Ft void
.Fn timespecadd "struct timespec *a" \
"struct timespec *b" "struct timespec *res"
.Ft void
.Fn timespecsub "struct timespec *a" \
"struct timespec *b" "struct timespec *res"
.Ft void
.Fn timespecclear "struct timespec *ts"
.Ft int
.Fn timespecisset "struct timespec *ts"
.Ft int
.Fn timespeccmp "struct timespec *a" "struct timespec b" CMP
.Sh DESCRIPTION
These macros are provided for manipulating the
.Fa timeval
and
.Fa timespec
structures described in
.Xr timeval 3 .
.Pp
The
.Fn timeradd
and
.Fn timespecadd
macros add the time information stored in
.Fa a
to
.Fa b ,
storing the result in
.Fa res .
With
.Fn timeradd
the results are simplified such that the value of
.Fa res->tv_usec
is always less than 1,000,000 (1 second).
With
.Fn timespecadd
the
.Fa res->tv_nsec
member of
.Fa struct timespec
is always less than 1,000,000,000.
.Pp
The
.Fn timersub
and
.Fn timespecsub
macros subtract the time information stored in
.Fa b
from
.Fa a
and store the resulting structure
in
.Fa res .
.Pp
The
.Fn timerclear
and
.Fn timespecclear
macros initialize the structures
to midnight (0 hour) January 1st, 1970 (the Epoch).
In other words, they set the members of the structure to zero.
.Pp
The
.Fn timerisset
and
.Fn timespecisset
macros return true if the input structure
is set to any time value other than the Epoch.
.Pp
The
.Fn timercmp
and
.Fn timespeccmp
macros compare
.Fa a
to
.Fa b
using the comparison operator given in
.Fa CMP .
The result of the comparison is returned.
.Sh SEE ALSO
.Xr timeval 3
.Sh HISTORY
The
.Fn timeradd
family of macros first appeared in
.Nx 1.1 .
These were later ported to
.Fx 2.2.6 .
The
.Fn timespec
family of macros first appeared in
.Nx 1.2 .