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2017-09-15
Aliases: timerclear(3), timerclear(3), timerclear(3), timerclear(3), timerclear(3), timerclear(3), timercmp(3), timercmp(3), timercmp(3), timercmp(3), timercmp(3), timercmp(3), timerisset(3), timerisset(3), timerisset(3), timerisset(3), timerisset(3), timerisset(3), timersub(3), timersub(3), timersub(3), timersub(3), timersub(3), timersub(3)

manpages-dev

Manual pages about using GNU/Linux for development

man-pages

Linux kernel and C library user-space interface documentation

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);
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

DESCRIPTION

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(..., !=)

RETURN VALUE

timerisset() and timercmp() return true (nonzero) or false (0).

ERRORS

No errors are defined.

CONFORMING TO

Not in POSIX.1. Present on most BSD derivatives.

REFERENCED BY

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