Time Library
The Time Library contains functions and type definitions for time calculations in the UNIX time format which counts the number of seconds since the "epoch". This is very convenient for programs that work with time intervals: the difference between two UNIX time values is a real-time difference measured in seconds.
What is the epoch?
Originally it was defined as the beginning of 1970 GMT. (January 1, 1970 Julian day)
GMT, Greenwich Mean Time, is a traditional term for the time zone in England.
The TimeStruct type is a structure type suitable for time and date storage.
Library Routines
Time_dateToEpoch
Prototype |
function Time_dateToEpoch(var ts : TimeStruct) : longint; |
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Description |
This function returns the UNIX time : number of seconds since January 1, 1970 0h00mn00s. |
Parameters |
|
Returns |
Number of seconds since January 1, 1970 0h00mn00s. |
Requires |
Nothing. |
Example |
var ts1 : TimeStruct; Epoch : longint; ... // what is the epoch of the date in ts ? epoch := Time_dateToEpoch(@ts1) ; |
Notes |
None. |
Time_epochToDate
Prototype |
procedure Time_epochToDate(e : longint; var ts : TimeStruct); |
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Description |
Converts the UNIX time to time and date. |
Parameters |
|
Returns |
Nothing. |
Requires |
Nothing. |
Example |
var ts2 : TimeStruct; epoch : longint; ... //what date is epoch 1234567890 ? epoch := 1234567890 ; Time_epochToDate(epoch,ts2); |
Notes |
None. |
Time_dateDiff
Prototype |
function Time_dateDiff(var t1, t2 : TimeStruct) : longint ; |
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Description |
This function compares two dates and returns time difference in seconds as a signed long.
Result is positive if |
Parameters |
|
Parameters |
None. |
Returns |
Time difference in seconds as a signed long. |
Requires |
Nothing. |
Example |
var ts1, ts2 : TimeStruct; diff : longint; ... //how many seconds between these two dates contained in ts1 and ts2 buffers? diff := Time_dateDiff(ts1, ts2); |
Notes |
None. |
Library Example
Demonstration of Time library routines usage for time calculations in UNIX time format.
program Time_Demo; {* * simple time structure *} type TimeStruct = record ss : byte ; // seconds mn : byte ; // minutes hh : byte ; // hours md : byte ; // day in month, from 1 to 31 wd : byte ; // day in week, monday=0, tuesday=1, .... sunday=6 mo : byte ; // month number, from 1 to 12 (and not from 0 to 11 as with unix C time !) yy : word ; // year Y2K compliant, from 1892 to 2038 end; var ts1, ts2 : TimeStruct; buf : array[256] of byte ; epoch, diff : longint ; begin ts1.ss := 0 ; ts1.mn := 7 ; ts1.hh := 17 ; ts1.md := 23 ; ts1.mo := 5 ; ts1.yy := 2006 ; {* * what is the epoch of the date in ts ? *} epoch := Time_dateToEpoch(@ts1) ; // epoch = 1148404020 {* * what date is epoch 1234567890 ? *} epoch := 1234567890 ; Time_epochToDate(epoch, @ts2) ; // ts2.ss := 30 ; // ts2.mn := 31 ; // ts2.hh := 23 ; // ts2.md := 13 ; // ts2.wd := 4 ; // ts2.mo := 2 ; // ts2.yy := 2009 ; {* * how much seconds between this two dates ? *} diff := Time_dateDiff(@ts1, @ts2) ; // diff = 86163870 end.
TimeStruct type definition
type TimeStruct = record ss : byte ; // seconds mn : byte ; // minutes hh : byte ; // hours md : byte ; // day in month, from 1 to 31 wd : byte ; // day in week, monday=0, tuesday=1, .... sunday=6 mo : byte ; // month number, from 1 to 12 (and not from 0 to 11 as with unix C time !) yy : word ; // year Y2K compliant, from 1892 to 2038 end;
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