Convert boost ptime from GMT to UTC

I am trying to convert boost::posix_time::ptime from GMT to UTC. I went on Boost web site, and most of the examples are for US time zone, but I need the GMT one.

All I need is the right parameters to put in boost::date_time::local_adju开发者_JAVA技巧stor

Thanks.

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Ok, assuming this is WET your string should be (Summertime is from last Sunday in April, 2:00 until last Sunday in October, 3:00):

"WET-0WEST,M4.5.0/02:00:00,M10.5.0/03:00:00"