Issue converting time to timestamp

Silver Diamond

I am coding in C++ in CCS6.1.1

the include directory points to ~/ti/ccsv6/tools/compiler/ti-cgt-msp430_4.4.5/include

tm Tm;

// set every field to zero
Tm.tm_sec = 0;      /* seconds after the minute   - [0,59]  */
Tm.tm_min = 0;      /* minutes after the hour     - [0,59]  */
Tm.tm_hour = 0;     /* hours after the midnight   - [0,23]  */
Tm.tm_mday = 0;     /* day of the month           - [1,31]  */
Tm.tm_mon = 0;      /* months since January       - [0,11]  */
Tm.tm_year = 0;     /* years since 1900                     */
Tm.tm_wday = 0;     /* days since Sunday          - [0,6]   */
Tm.tm_yday = 0;     /* days since Jan 1st         - [0,365] */
Tm.tm_isdst = 0;    /* Daylight Savings Time flag           */

Tm.tm_year = 46;
Tm.tm_mon = 2;
Tm.tm_day = 23;
Tm.tm_hour = 9;
Tm.tm_min = 3;
Tm.tm_sec = 38;

time_t epoch = mktime(&Tm);

epoch => 1458651818
going to: http://www.epochconverter.com/

outputs:

Tue 22 Mar 2016 09:03:38 AM EDT GMT-4:00 DST

WHY? I am setting day to 23, not 22, why is my epoch converting to 23rd? What
is the recommended way to fix it?

But if I set the year to 116, my result is even worse. Am I doing something wrong?

EDIT:

I tried the following on my Linux machine:

#include <stdio.h>
#include <time.h>

int main() {
    // set every field to zero
    tm Tm;
    Tm.tm_sec = 0;      /* seconds after the minute   - [0,59]  */
    Tm.tm_min = 0;      /* minutes after the hour     - [0,59]  */
    Tm.tm_hour = 0;     /* hours after the midnight   - [0,23]  */
    Tm.tm_mday = 0;     /* day of the month           - [1,31]  */
    Tm.tm_mon = 0;      /* months since January       - [0,11]  */
    Tm.tm_year = 0;     /* years since 1900                     */
    Tm.tm_wday = 0;     /* days since Sunday          - [0,6]   */
    Tm.tm_yday = 0;     /* days since Jan 1st         - [0,365] */
    Tm.tm_isdst = 0;    /* Daylight Savings Time flag           */

    Tm.tm_year = 116;
    Tm.tm_mon = 2;
    Tm.tm_mday = 23;
    Tm.tm_hour = 9;
    Tm.tm_min = 3;
    Tm.tm_sec = 38;

    time_t epoch = mktime(&Tm);

    printf("Epoch is: %ld\n", epoch);
    return 0;
}

This worked fine on my Linux machine using Linux time.h, result is 1458741818, converting it at http://www.epochconverter.com/ produces `Wed 23 Mar 2016 10:03:38`

The same code snippet on MSP430 using ti-cgt-map430_4.4.5 produces result: 3667712618, converting it produces `Sat 23 Mar 2086 05:03:38 AM EDT GMT-4:00 DST`

Is there an issue with the Library?

over 9 years ago

0 Jon Zarate over 9 years ago

Expert 1190 points

I never used that before, but are you sure that is the real output of that code ?
You set the tm_year to 46 ( "years since 1900" ) and the output says 2016 ?
For me looks like you are executing other code than that, I may be mistaken though.

0 Silver Diamond over 9 years ago in reply to Jon Zarate

Genius 4010 points

Jon, I talk about it in the question, yes it should be 116, but if I do that then the epoch comes out as: 3667712618, see the question.

0 Jon Zarate over 9 years ago in reply to Silver Diamond

Expert 1190 points

I just wanted to point out that having that many errors in a library is suspicious. The day, year and hour values are wrong.

(You set it to 9 hours, following your comment /* hours after the midnight - [0,23] */ the output value should be 9 instead of 10, just like the minutes or seconds.)

This all looks weird, that's why I was searching for a more global answer, like maybe executing other code by mistake, maybe the comments are not accurate for this platform library etc. As I said, I haven't used it before.

Good luck.

0 Archaeologist over 9 years ago

TI__Guru* 84285 points

The TI RTS does not use the POSIX epoch for the basis of time_t, it uses UTC-6 January 1, 1900.

See http://processors.wiki.ti.com/index.php/Time_and_clock_RTS_Functions

See also https://e2e.ti.com/support/development_tools/compiler/f/343/t/493367 for a recent discussion.

0 Silver Diamond over 9 years ago in reply to Jon Zarate

Genius 4010 points

Jon, the Tm.tm_isdst is set to zero that is why output is 9, its fine. The problem is the day of the month. Lookign at mktime.c , the return is not from 1970, but rather from 1900, so setting year to 116 and subtracting seconds between 1900 and 1970 from result provides the right answer. This is not standard behaviour of mktime function. Is there reference documentation for TI standard library? I need this verified.

0 Silver Diamond over 9 years ago in reply to Archaeologist

Genius 4010 points

The fact that it is not a unix epoch is soooooo uncool....

0 Archaeologist over 9 years ago in reply to Silver Diamond

TI__Guru* 84285 points

Then upgrade to the cool MSP430 compiler version 15.12.0.LTS or higher, and use the option -D__TI_TIME_USES_64 to get 64-bit time_t, which uses the POSIX epoch.

0 Silver Diamond over 9 years ago in reply to Archaeologist

Genius 4010 points

:-)

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Issue converting time to timestamp