.\" $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>
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.\" 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
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.\" $FreeBSD: src/share/man/man3/timeradd.3,v 1.3 2003/09/08 19:57:19 ru Exp $
.\"
.Dd June 7, 2010
.Dt timeradd 3bsd
.Os
.Sh NAME
.Nm timeradd ,
.Nm timersub ,
.Nm timerclear ,
.Nm timerisset ,
.Nm timercmp ,
.Nm timespecadd ,
.Nm timespecsub ,
.Nm timespecclear ,
.Nm timespecisset ,
.Nm timespeccmp
.Nd operations on time structure
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.ds doc-str-Lb-libbsd \*[str-Lb-libbsd]
.Lb libbsd
.Sh SYNOPSIS
.In sys/time.h
(See
.Xr libbsd 7
for include usage.)
.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 3bsd .
.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 3bsd
.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 .