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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON |
TIMERADD(3) Linux Programmer's Manual TIMERADD(3)
timeradd, timersub, timercmp, timerclear, timerisset - timeval opera‐
tions
#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);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
All functions shown above:
Since glibc 2.19:
_DEFAULT_SOURCE
Glibc 2.19 and earlier:
_BSD_SOURCE
The macros are provided to operate on timeval structures, defined in
<sys/time.h> as:
struct timeval {
time_t tv_sec; /* seconds */
suseconds_t tv_usec; /* microseconds */
};
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(..., !=)
timerisset() and timercmp() return true (nonzero) or false (0).
No errors are defined.
Not in POSIX.1. Present on most BSD derivatives.
gettimeofday(2), time(7)
This page is part of release 4.12 of the Linux man-pages project. A
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latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2016-03-15 TIMERADD(3)
Pages that refer to this page: gettimeofday(2), time(7)