ChorusOS man pages section 2POSIX: POSIX System Calls

settimeofday(2POSIX)

NAME

gettimeofday, settimeofday- get/set date and time

SYNOPSIS

#include <sys/time.h>

tp

tzp

tp

tzp

DESCRIPTION

The current Greenwich time and the current time zone on the system are obtained using the gettimeofday call, and set with the settimeofday call. The time is expressed as the number of 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 tp or tzp is NULL, the associated time information will not be returned or set.

The structures pointed to by tp and tzp are defined in sys/time.h 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 timezone structure indicates the local time zone (measured in minutes of time westward from Greenwich), and a flag that, if non zero, 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

If successful, gettimeofday returns 0, otherwise it returns -1, and sets errno to indicate one of the following error conditions.

ERRORS

[EFAULT]: The address of an argument referenced invalid memory.
[EPERM]: A user other than the super-user attempted to set the time.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving