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settimeofday(2) [netbsd man page]

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

NAME
gettimeofday, settimeofday -- get/set date and time LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/time.h> int gettimeofday(struct timeval * restrict tp, void * restrict tzp); int settimeofday(const struct timeval * restrict tp, const void * restrict tzp); DESCRIPTION
Note: time zone information is no longer provided by this interface. See localtime(3) for information on how to retrieve it. The system's notion of the current UTC time 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 is NULL, the time will not be returned or set. Despite being declared void *, the objects pointed to by tzp shall be of type struct timezone. The structures pointed to by tp and tzp are defined in <sys/time.h>. The first one is described in timeval(3) and the latter legacy struc- ture is defined as: struct timezone { int tz_minuteswest; /* of Greenwich */ int tz_dsttime; /* type of dst correction to apply */ }; The timezone structure is provided only for source compatibility. It is ignored by settimeofday(), and gettimeofday() will always return zeroes. If the calling user is not the super-user, then the settimeofday() function in the standard C library will try to use the clockctl(4) device if present, thus making possible for non privileged users to set the system time. If clockctl(4) is not present or not accessible, then settimeofday() reverts to the settimeofday() system call, which is restricted to the super user. RETURN VALUES
A return value 0 indicates that the call succeeded. A return value -1 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: [EFAULT] An argument address referenced invalid memory. [EPERM] A user other than the super user attempted to set the time, or the specified time was less than the current time, which was not permitted at the current security level. SEE ALSO
date(1), adjtime(2), ctime(3), localtime(3), clockctl(4), timed(8) HISTORY
The gettimeofday() function call appeared in 4.2BSD. The tzp argument was deprecated in 4.4BSD (and many other systems). BSD
May 18, 2010 BSD

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GETTIMEOFDAY(2) 						System Calls Manual						   GETTIMEOFDAY(2)

NAME
gettimeofday, settimeofday - get/set date and time SYNOPSIS
#include <sys/time.h> gettimeofday(tp, tzp) struct timeval *tp; struct timezone *tzp; settimeofday(tp, tzp) struct timeval *tp; struct timezone *tzp; DESCRIPTION
The system's notion of the current Greenwich time and the current time zone is obtained with the gettimeofday call, and set with the set- timeofday 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 tzp is zero, the time zone 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 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: [EFAULT] An argument address referenced invalid memory. [EPERM] A user other than the super-user attempted to set the time. SEE ALSO
date(1), adjtime(2), ctime(3), timed(8) 4th Berkeley Distribution May 14, 1986 GETTIMEOFDAY(2)

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