gettimeofday
Hurricane Electric Internet Services
NAME
gettimeofday, settimeofday - get / set time
SYNOPSIS
#include <sys/time.h>
#include <unistd.h>
int gettimeofday(struct timeval *tv, struct timezone *tz);
int settimeofday(const struct timeval *tv , const struct
timezone *tz);
DESCRIPTION
gettimeofday and settimeofday can set the time as well as
a timezone. tv is a timeval struct, as specified in
/usr/include/sys/time.h:
struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
and tz is a timezone :
struct timezone {
int tz_minuteswest;
/* minutes west of Greenwich */
int tz_dsttime;
/* type of dst correction */
};
With daylight savings times defined as follows :
DST_NONE /* not on dst */
DST_USA /* USA style dst */
DST_AUST /* Australian style dst */
DST_WET /* Western European dst */
DST_MET /* Middle European dst */
DST_EET /* Eastern European dst */
DST_CAN /* Canada */
DST_GB /* Great Britain and Eire */
DST_RUM /* Rumania */
DST_TUR /* Turkey */
DST_AUSTALT /* Australian style with shift in 1986 */
And the following macros are defined to operate on this :
#define timerisset(tvp)\
((tvp)->tv_sec || (tvp)->tv_usec)
#define timercmp(tvp, uvp, cmp)\
((tvp)->tv_sec cmp (uvp)->tv_sec ||\
(tvp)->tv_sec == (uvp)->tv_sec &&\
(tvp)->tv_usec cmp (uvp)->tv_usec)
#define timerclear(tvp)
((tvp)->tv_sec = (tvp)->tv_usec = 0)
If either tv or tz is null, the corresponding structure is
not set or returned.
Only the super user may use settimeofday.
ERRORS
EPERM settimeofday is called by someone other than the
superuser.
EINVAL Timezone (or something else) is invalid.
CONFORMING TO
BSD 4.3
SEE ALSO
date(1), adjtimex(2), time(2), ctime(3), ftime(3)
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.