time_from_decimal_day mktime

[KammutierSpule]

I'm not sure if this is working as expected:

  struct std::tm epoch = {0};
  epoch.tm_isdst = 0;
  epoch.tm_sec = epoch.tm_min = epoch.tm_hour = epoch.tm_mon = 0;
  epoch.tm_mday = 1;
  epoch.tm_year = 70;
  time_t local_tz_offset = mktime(&epoch);
...
  return mktime(&t) - local_tz_offset;

I'm getting local_tz_offset -3600 on my computer.

but the thing is that mktime looks is not following the timezone offsets.
In fact, what was correct to me, was to not use this local_tz_offset adjust.
Now because of the - (-3600) it gives me +1hour

[KammutierSpule]

I found this related blog post, maybe useful to anyone:
http://kbyanc.blogspot.com/2007/06/c-converting-struct-tm-times-with.html