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| 32 | .\" @(#)gettimeofday.2 6.11 (Berkeley) 3/10/91 |
| 33 | .\" |
| 34 | .Dd March 10, 1991 |
| 35 | .Dt GETTIMEOFDAY 2 |
| 36 | .Os BSD 4 |
| 37 | .Sh NAME |
| 38 | .Nm gettimeofday , |
| 39 | .Nm settimeofday |
| 40 | .Nd get/set date and time |
| 41 | .Sh SYNOPSIS |
| 42 | .Fd #include <sys/time.h> |
| 43 | .Ft int |
| 44 | .Fn gettimeofday "struct timeval *tp" "struct timezone *tzp" |
| 45 | .Ft int |
| 46 | .Fn settimeofday "struct timeval *tp" "struct timezone *tzp" |
| 47 | .Sh DESCRIPTION |
| 48 | .Bf -symbolic |
| 49 | Note: timezone is no longer used; this information is kept outside |
| 50 | the kernel. |
| 51 | .Ef |
| 52 | The system's notion of the current Greenwich time and the current time |
| 53 | zone is obtained with the |
| 54 | .Fn gettimeofday |
| 55 | call, and set with the |
| 56 | .Fn settimeofday |
| 57 | call. The time is expressed in seconds and microseconds |
| 58 | since midnight (0 hour), January 1, 1970. The resolution of the system |
| 59 | clock is hardware dependent, and the time may be updated continuously or |
| 60 | in ``ticks.'' If |
| 61 | .Fa tp |
| 62 | or |
| 63 | .Fa tzp |
| 64 | is NULL, the associated time |
| 65 | information will not be returned or set. |
| 66 | .Pp |
| 67 | The structures pointed to by |
| 68 | .Fa tp |
| 69 | and |
| 70 | .Fa tzp |
| 71 | are defined in |
| 72 | .Ao Pa sys/time.h Ac |
| 73 | as: |
| 74 | .Pp |
| 75 | .Bd -literal |
| 76 | struct timeval { |
| 77 | long tv_sec; /* seconds since Jan. 1, 1970 */ |
| 78 | long tv_usec; /* and microseconds */ |
| 79 | }; |
| 80 | |
| 81 | struct timezone { |
| 82 | int tz_minuteswest; /* of Greenwich */ |
| 83 | int tz_dsttime; /* type of dst correction to apply */ |
| 84 | }; |
| 85 | .Ed |
| 86 | .Pp |
| 87 | The |
| 88 | .Fa timezone |
| 89 | structure indicates the local time zone |
| 90 | (measured in minutes of time westward from Greenwich), |
| 91 | and a flag that, if nonzero, indicates that |
| 92 | Daylight Saving time applies locally during |
| 93 | the appropriate part of the year. |
| 94 | .Pp |
| 95 | Only the super-user may set the time of day or time zone. |
| 96 | .Sh RETURN |
| 97 | A 0 return value indicates that the call succeeded. |
| 98 | A -1 return value indicates an error occurred, and in this |
| 99 | case an error code is stored into the global variable |
| 100 | .Va errno . |
| 101 | .Sh ERRORS |
| 102 | The following error codes may be set in |
| 103 | .Va errno : |
| 104 | .Bl -tag -width [EFAULT] |
| 105 | .It Bq Er EFAULT |
| 106 | An argument address referenced invalid memory. |
| 107 | .It Bq Er EPERM |
| 108 | A user other than the super-user attempted to set the time. |
| 109 | .El |
| 110 | .Sh SEE ALSO |
| 111 | .Xr date 1 , |
| 112 | .Xr adjtime 2 , |
| 113 | .Xr ctime 3 , |
| 114 | .Xr timed 8 |
| 115 | .Sh HISTORY |
| 116 | The |
| 117 | .Nm |
| 118 | function call appeared in |
| 119 | .Bx 4.2 . |