Name
timeradd, timersub, timercmp, timerclear, timerisset — timeval operations
Synopsis
#include <sys/time.h>
void timeradd( |
struct timeval *a, |
| struct timeval *b, | |
struct timeval *res); |
void timersub( |
struct timeval *a, |
| struct timeval *b, | |
struct timeval *res); |
void timerclear( |
struct timeval *tvp); |
int timerisset( |
struct timeval *tvp); |
int timercmp( |
struct timeval *a, |
| struct timeval *b, | |
CMP); |
![[Note]](../stylesheet/note.png) |
Note | ||
|---|---|---|---|
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DESCRIPTION
The macros are provided to operate on timeval structures, defined in
<sys/time.h>
as:
struct timeval { time_t tv_sec;suseconds_t tv_usec;};
timeradd() adds the time
values in a and
b, and places the sum
in the timeval pointed to by
res. The result is
normalized such that res−>tv_usec has a
value in the range 0 to 999,999.
timersub() subtracts the
time value in b from
the time value in a,
and places the result in the timeval pointed to by res. The result is normalized
such that res−>tv_usec has a
value in the range 0 to 999,999.
timerclear() zeros out the
timeval structure pointed to
by tvp, so that it
represents the Epoch: 1970-01-01 00:00:00 +0000 (UTC).
timerisset() returns true
(nonzero) if either field of the timeval structure pointed to by
tvp contains a
nonzero value.
timercmp() compares the
timer values in a and
b using the
comparison operator CMP, and returns true (nonzero)
or false (0) depending on the result of the comparison. Some
systems (but not Linux/glibc), have a broken timercmp() implementation, in which
CMP of >=, <=, and == do not work; portable
applications can instead use
!timercmp(..., <) !timercmp(..., >) !timercmp(..., !=)
COLOPHON
This page is part of release 3.24 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/.
|
Copyright (c) 2007 by Michael Kerrisk <mtk.manpagesgmail.com> Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. 2007-07-31, mtk, Created |