date_time local to UTC conversion

hi. i am using boost::date_time i am using ptime always in UTC. but some time i have to interact with user. therefore i need to convert the ptime to the local ptime back and forth. int foo () { ptime mytime_asutc = some_UTC_time; ptime mytime_aslocal = XXX (mytime_asutc); ptime histime_aslocal = some_local_time; ptime histime_asutc = YYY (histime_aslocal); } i am in germany, so i'd like to use germany local settings. best would be to get all information from unix TZ variable. but i found out, only one direction of conversion works with unix TZ. the other one needs manual input. i don't understand the eu_dst_trait stuff. i'd very much appreciate to have XXX and YYY. cu & thx erik -- Erik Thiele