On 12/18/19 10:24 AM, Walter H. wrote:
Hello,
I tried your programme on my system (other linux distribution), and got the same result;
even on windows the same results;
but this is interesting
# date --date="Dec 1 00:00:00 2019" +"%s"
1575154800
# date --date="Nov 30 23:59:59 2019" +"%s"
1575154799
there you have this 1 second difference;
I'd say mktime seens to be buggy ...
Walter
On 18.12.2019 15:17, Jouk Jansen wrote:
Hi All,
I'm strugling with the C-function mktime. According to the man-pages it
returns "seconds since the Epoch". I tried to use this functions to get
differnces from two date-times , but was could not interpret the result.
When trying to get the diffrence between 30 Nov 2019 23:59:59 and 1 Dec 2019
00:00:00 (see code below) I expected to find 1 second difference but I find:
1577746799 1577833200 -86401
As output of the sample program. (and not 1577833199 1577833200 -1)
How should I read "seconds since the Epoch"????
Is the output of mktime correct?
(I also tried 31 Nov and got the expected 1 second)
(should mktime not give an error for 31 Nov??)
Regards
Jouk
Code :
#include<stdio.h>
#include<time.h>
main()
{
struct tm time_str , time_str2;
time_str.tm_sec = 59; //30 Nov 2019 23:59:59
time_str.tm_min = 59;
time_str.tm_hour = 23;
time_str.tm_mday = 30;
time_str.tm_mon = 11;
time_str.tm_year = 119;
time_str.tm_isdst = 0;
time_str2.tm_sec = 0; // 1 Dec 2019 00:00:00
time_str2.tm_min = 0;
time_str2.tm_hour = 0;
time_str2.tm_mday = 1;
time_str2.tm_mon = 12;
time_str2.tm_year = 119;
time_str2.tm_isdst = 0;
printf( "%d %d %d\n" , mktime(&time_str ) , mktime(&time_str2 ) ,
mktime(&time_str ) - mktime(&time_str2 ) );
}
remember that the month values (tm_mon) go from 0 to 11.
change tm_mon for November to 10 and for December to 11 and you get the expected result.
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