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POmktime shows inconsistent output
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Id
11293422
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AcceptedAnswerId
11293806
AnswerCount
5
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CommentCount
4
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CreationDate
2012-07-02T12:09:35.243
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0
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2014-08-18T11:18:02.307
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2014-06-02T22:41:17.207
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2366322
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1
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2084
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While trying to write code which returns 24 hours less than a given time, <code>mktime()</code>shows inconsistent output. I calculate it similar to this: <code>current_time(GMT) - 86400</code> which should return the right value. All we need to do is calculate based on the input time; we used <code>mktime()</code> to change the time and get the GMT time and then do the regular calculation. I included my code below. <pre><code>#include <stdio.h> #include <time.h> int main() { time_t currentTime, tempTime; struct tm *localTime; time(&currentTime); //localTime = localtime(&currentTime); localTime = gmtime(&currentTime); //get the time in GMT as we are in PDT printf("Time %2d:%02d\n", (localTime->tm_hour)%24, localTime->tm_min); localTime->tm_hour = 19; // Set the time to 19:00 GMT localTime->tm_min = 0; localTime->tm_sec = 0; tempTime = mktime(localTime); //tempTime = mktime(localTime) - timezone; printf("Current time is %ld and day before time is %ld\n", currentTime, (currentTime - 86400)); printf("Current timezone is %ld \n", timezone); printf("New time is %ld and day before time is %ld\n",tempTime, (tempTime - 86400)); } </code></pre> But when we check the output it is coming back incorrect after the call to call <code>mktime()</code>. Below is the output of above program. <pre><code>$ ./a.out Time 11:51 Current time is 1341229916 and day before time is 1341143516 New time is 1341284400 and day before time is 1341198000 $ ./print_gmt 1341229916 Mon Jul 2 11:51:56 2012 $ ./print_gmt 1341143516 Sun Jul 1 11:51:56 2012 $ ./print_gmt 1341284400 Tue Jul 3 03:00:00 2012 $ ./print_gmt 1341198000 Mon Jul 2 03:00:00 2012 $ date Mon Jul 2 04:52:46 PDT 2012 </code></pre> Now if we un-comment the line which subtracts the timezone (present in time.h), then the output is as expected. Below is the value for timezone in above program <pre><code>$ ./a.out . . . Current timezone is 28800 . . . </code></pre> So why is there such inconsistent behavior for <code>mktime()</code> although the man pages do not mention such adjustment of the timezone. Is there something we are missing while doing such conversions? Thanks in advance.
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<c><time><mktime>
Title
mktime shows inconsistent output
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PostAcceptedAnswerId
1. PO
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 PTAnswer
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1. This table or related slice is empty.
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1. PTQuestion
UserLastEditorUserId
1. UShellerve
UserOwnerUserId
1. USAbhinav
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1. This table or related slice is empty.
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1. PO
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2. PO
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3. PO
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