NAME

gettimeofday, settimeofday − get or set the date and time

SYNOPSIS

#include <sys/time.h>

int gettimeofday(struct timeval ∗tp);

int settimeofday(struct timeval ∗tp);

MT-LEVEL

MT-Safe

DESCRIPTION

gettimeofday() gets and settimeofday() sets the system’s notion of the current time.  The current time is expressed in elapsed seconds and microseconds since 00:00 Universal Coordinated Time, January 1, 1970.  The resolution of the system clock is hardware dependent; the time may be updated continuously or in clock ticks. 

tp points to a timeval structure, which includes the following members:

long    tv_sec;    /∗ seconds since Jan. 1, 1970 ∗/
long    tv_usec;   /∗ and microseconds ∗/

If tp is a null pointer, the current time information is not returned or set. 

The TZ environment variable holds time zone information.  See timezone(4). 

Only the privileged user may set the time of day. 

SEE ALSO

adjtime(2), ctime(3C), timezone(4)

RETURN VALUES

A −1 return value indicates that an error occurred and errno has been set. 

ERRORS

The following error codes may be set in errno:

EINVAL tp specifies an invalid time. 

EPERM A user other than the privileged user attempted to set the time or time zone. 

NOTES

The implementation of settimeofday() ignores the tv_usec field of tp.  If the time needs to be set with better than one second accuracy, call settimeofday() for the seconds and then adjtime() for finer accuracy. 

Sun Microsystems  —  Last change: 22 Jan 1993