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OpenDarwin 7.2.1 - man page for settimeofday (opendarwin section 2)

GETTIMEOFDAY(2) 		     BSD System Calls Manual			  GETTIMEOFDAY(2)

     gettimeofday, settimeofday -- get/set date and time

     #include <sys/time.h>

     gettimeofday(struct timeval *tp, struct timezone *tzp);

     settimeofday(const struct timeval *tp, const struct timezone *tzp);

     Note: timezone is no longer used; this information is kept outside the kernel.

     The system's notion of the current Greenwich time and the current time zone is obtained with
     the gettimeofday() call, and set with the 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 tp or tzp is NULL, the associated time information will not be returned or

     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 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.	If the system securelevel is
     greater than 1 (see init(8) ), the time may only be advanced.  This limitation is imposed to
     prevent a malicious super-user from setting arbitrary time stamps on files.  The system time
     can still be adjusted backwards using the adjtime(2) system call even when the system is

     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.

     The following error codes may be set in errno:

     [EFAULT]  An argument address referenced invalid memory.

     [EPERM]   A user other than the super-user attempted to set the time.

     date(1), adjtime(2), ctime(3), timed(8)

     The gettimeofday() function call appeared in 4.2BSD.

4th Berkeley Distribution		   May 26, 1995 		4th Berkeley Distribution

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