John Rocha
I do not believe date and time zone will tell you if the area is in day
light
savings or not. Because there are some areas that do not observe daylight savings. In the US, I know that Arizona is part of Mountain Time for the time zone, but they do not observe day light savings.
time_zone support in datetime library covers usage of DST extensively. Every timezone in datetime library can be defined with or without usage of DST. Since time_zone is one of the parameters to the constructor it carries DST information by definition. The actual reason for me to ask my question here was the exception caused by the conflict between this forth parameter and the DST settings that I was using in my timezone. Since then I moved to a another constructor, but the question remains - why do we have to supply the forth parameter when the timezone parameter defines usage of DST.