GETTIMEOFDAY

Section: System Calls (2)
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BSD mandoc
BSD 4

NAME

gettimeofday settimeofday - get/set date and time

SYNOPSIS

Fd #include <sys/time.h> Ft int Fn gettimeofday struct timeval *tp struct timezone *tzp Ft int Fn settimeofday struct timeval *tp struct timezone *tzp

DESCRIPTION

Bf -symbolic Note: timezone is no longer used; this information is kept outside the kernel. Ef The system's notion of the current Greenwich time and the current time zone is obtained with the Fn gettimeofday call, and set with the Fn settimeofday call. The time is expressed in seconds and microseconds since midnight (0 hour), January 1, 1970. The resolution of the system clock is hardware dependent, and the time may be updated continuously or in ``ticks.'' If Fa tp or Fa tzp is NULL, the associated time information will not be returned or set.

The structures pointed to by Fa tp and Fa tzp are defined in Ao Pa sys/time.h Ac as:

struct timeval {
        long    tv_sec;         /* seconds since Jan. 1, 1970 */
        long    tv_usec;        /* and microseconds */
};

struct timezone {
        int     tz_minuteswest; /* of Greenwich */
        int     tz_dsttime;     /* type of dst correction to apply */
};

The Fa timezone structure indicates the local time zone (measured in minutes of time westward from Greenwich), and a flag that, if nonzero, indicates that Daylight Saving time applies locally during the appropriate part of the year.

Only the super-user may set the time of day or time zone.

RETURN

A 0 return value indicates that the call succeeded. A -1 return value indicates an error occurred, and in this case an error code is stored into the global variable errno

ERRORS

The following error codes may be set in errno

Bq Er EFAULT: An argument address referenced invalid memory.
Bq Er EPERM: A user other than the super-user attempted to set the time.

HISTORY

The Fn gettimeofday function call appeared in BSD 4.2

This document was created by man2html, using the manual pages.
Time: 16:28:59 GMT, April 18, 2022