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28 .\" @(#)gettimeofday.2 8.2 (Berkeley) 5/26/95
37 .Nd get/set date and time
43 .Fn gettimeofday "struct timeval *tp" "struct timezone *tzp"
45 .Fn settimeofday "const struct timeval *tp" "const struct timezone *tzp"
48 Note: timezone is no longer used; this information is kept outside
52 The system's notion of the current Greenwich time and the current time
53 zone is obtained with the
55 system call, and set with the
58 The time is expressed in seconds and microseconds
59 since midnight (0 hour), January 1, 1970.
60 The resolution of the system
61 clock is hardware dependent, and the time may be updated continuously or
68 is NULL, the associated time
69 information will not be returned or set.
71 The structures pointed to by
81 time_t tv_sec; /* seconds */
82 suseconds_t tv_usec; /* and microseconds */
86 int tz_minuteswest; /* minutes west of Greenwich */
87 int tz_dsttime; /* type of dst correction */
93 structure indicates the local time zone
94 (measured in minutes of time westward from Greenwich),
95 and a flag that, if nonzero, indicates that
96 Daylight Saving time applies locally during
97 the appropriate part of the year.
99 Only the super-user may set the time of day or time zone.
100 If the system is running at securelevel >= 2 (see
102 the time may only be advanced or retarded by a maximum of one second.
103 This limitation is imposed to prevent a malicious super-user
104 from setting arbitrary time stamps on files.
105 The system time can be adjusted backwards without restriction using the
107 system call even when the system is secure.
111 The following error codes may be set in
115 An argument address referenced invalid memory.
117 A user other than the super-user attempted to set the time.
122 .Xr clock_gettime 2 ,
130 system call appeared in