_tzset and x letter time-zone names - c

Question

How can I set, in C, the time zone for Saint Pierre and Miquelon (PMST3PMDT) with this format:
set TZ=tzn[+ | –]hh[:mm[:ss] ][dzn]
If you look at the documentation of _tzset, you can read that:
tzn
Three-letter time-zone name, such as PST. You must specify the correct offset from local time to UTC.
What about time zone names of 4 letters (PMDT) or 5 letters (EASST) ?
Here is the list of all the time zone abbreviations: wikiepedia
Here is my simple code in C to test _tzset:
#include <stdio.h>
#include <stdlib.h>
#include <sys/timeb.h>
#include <time.h>
//add _CRT_SECURE_NO_WARNINGS in the project properties "preprocessor definitions"
int main(int argc, char* argv[])
{
time_t t;
struct tm * now;
_putenv("TZ=PST8PDT"); // for pacific standard time, there is no problem
_tzset();
t = time(0);
now = localtime( & t );
printf("time: %d:%d \nisdst:%d\n", now->tm_hour, now->tm_min, now->tm_isdst);
printf("_daylight=%d\n", _daylight);
printf( "_timezone=%d\n", _timezone);
printf( "_tzname[0]=%s\n", _tzname[0]);
printf( "_tzname[1]=%s\n", _tzname[1]);
return 0;
}
*I'm using windows8, visual studio 2012

Answer 1

From what I see in the timezone database on Ubuntu:
/usr/share/zoneinfo/zone.tab
The timezone you want to use is named America/Miquelon.
So you would want to do this:
setenv("TZ", "America/Miquelon", 1);
tzset();
To force the timezone to Saint Pierre & Miquelon.
I do not know whether that would work under MS-Windows though...