projects / unix-history / blame
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1 | .\" Copyright (c) 1980 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 1347a72e | 5 | .\" @(#)gettimeofday.2 6.8 (Berkeley) %G% |
| 03365d4a | 6 | .\" |
| 8c6e89a6 | 7 | .TH GETTIMEOFDAY 2 "" |
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8 | .UC 4 |
| 9 | .SH NAME | |
| a2364113 | 10 | gettimeofday, settimeofday \- get/set date and time |
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11 | .SH SYNOPSIS |
| 12 | .nf | |
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13 | .ft B |
| 14 | #include <sys/time.h> | |
| 15 | .PP | |
| 16 | .ft B | |
| 17 | gettimeofday(tp, tzp) | |
| 18 | struct timeval *tp; | |
| 19 | struct timezone *tzp; | |
| 20 | .PP | |
| 21 | .ft B | |
| 22 | settimeofday(tp, tzp) | |
| 23 | struct timeval *tp; | |
| 24 | struct timezone *tzp; | |
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25 | .fi |
| 26 | .SH DESCRIPTION | |
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27 | The system's notion of the current Greenwich time and the current time |
| 28 | zone is obtained with the \fIgettimeofday\fP call, and set with the | |
| 29 | \fIsettimeofday\fP call. The time is expressed in seconds and microseconds | |
| 30 | since midnight (0 hour), January 1, 1970. The resolution of the system | |
| 31 | clock is hardware dependent, and the time may be updated continuously or | |
| 32 | in ``ticks.'' If \fItp\fP or \fItzp\fP is NULL, the associated time | |
| 33 | information will not be returned or set. | |
| 03365d4a | 34 | .PP |
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35 | The structures pointed to by |
| 36 | .I tp | |
| 37 | and | |
| 38 | .I tzp | |
| 39 | are defined in | |
| 40 | .I <sys/time.h> | |
| 41 | as: | |
| 42 | .PP | |
| 43 | .nf | |
| 44 | .RS | |
| 45 | .DT | |
| 46 | struct timeval { | |
| db2c4838 | 47 | long tv_sec; /* seconds since Jan. 1, 1970 */ |
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48 | long tv_usec; /* and microseconds */ |
| 49 | }; | |
| 50 | .sp 1 | |
| 51 | struct timezone { | |
| 52 | int tz_minuteswest; /* of Greenwich */ | |
| 53 | int tz_dsttime; /* type of dst correction to apply */ | |
| 54 | }; | |
| 55 | .RE | |
| 56 | .fi | |
| 57 | .PP | |
| 58 | The | |
| 59 | .I timezone | |
| 60 | structure indicates the local time zone | |
| 61 | (measured in minutes of time westward from Greenwich), | |
| 62 | and a flag that, if nonzero, indicates that | |
| 63 | Daylight Saving time applies locally during | |
| 64 | the appropriate part of the year. | |
| 65 | .PP | |
| db2c4838 | 66 | Only the super-user may set the time of day or time zone. |
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67 | .SH RETURN |
| 68 | A 0 return value indicates that the call succeeded. | |
| 69 | A \-1 return value indicates an error occurred, and in this | |
| 70 | case an error code is stored into the global variable \fIerrno\fP. | |
| 71 | .SH "ERRORS | |
| 72 | The following error codes may be set in \fIerrno\fP: | |
| 73 | .TP 15 | |
| 74 | [EFAULT] | |
| 75 | An argument address referenced invalid memory. | |
| 76 | .TP 15 | |
| 77 | [EPERM] | |
| 78 | A user other than the super-user attempted to set the time. | |
| 79 | .SH "SEE ALSO" | |
| db2c4838 | 80 | date(1), adjtime(2), ctime(3), timed(8) |