le 2001/10/16 12:52, Pete à furbies@... a écrit :

> I know how far ahead/behind I am from GMT, and how far ahead/behind the
> other place is from GMT. What I can't get my very very very very very very
> very very very very very very small brain around is, how to calc the
> difference in hours/minutes
> 
> Does anyone have an FN that might get me where I want to go ?

untested.

but is this something along the lines of what you're seeking?
you didn't say if you had changed times to decimal so i supposed that they
were strings formatted like in a mail/http header.

i expect alain, jay and ken can reduce this down to a bout 4 lines, and then
someone else will say that there is a toolbox call that does it all in one.
meantimes, test and have fun.

:-j


// expects a string formatted "01:11,+21:15", "01:11,-21:15"
// or "HH:MM,Shh:mm"
// where "01:11"  [HH:MM] is local time
//       "+21:15" [Shh:mm] is the difference from GMT
//       and [S] the sign.
// returns a string "HH:MM" in GMT
local fn trad2GMT$( theStr as str255)
 dim localHr  as int
 dim localMn  as int
 dim 1 mySign$
 dim offGMTHr as int
 dim offGMTMn as int
'
localHr  = val( left$( theStr,2))
localMn  = val( mid$( theStr,4,2))
mySign$  = mid$( theStr,7,1)
// in case sign was forgotten
offGMTMn = val( right$( theStr,2))
offGMTHr = val( mid$( theStr, theStr[0] -4,2))
'
long if( mySign$ ="-")
// subtract
if( offGMTMn > localMn) then offGMTHr = offGMTHr +1 : localMn = localMn +60
localMn = localMn -offGMTMn
localHr = localHr -offGMTHr
xelse
// add
localMn = localMn +offGMTMn
if( localMn > 59) then localHr = localHr +1 : localMn = localMn -60
localHr = localHr +offGMTHr
end if
if( localHr >23) then localHr = localHr -24
// format return str$
theStr = str$( localMn)
theStr = right$( theStr, 2) : if theStr[1] =_" " then mid$( theStr,1,1) =
"0"
theStr = ":" +theStr
theStr = str$( localHr) +theStr
theStr = right$( theStr, 5) : if theStr[1] =_" " then mid$( theStr,1,1) =
"0"
'
end fn = theStr


// compare two formatted time trings with gmt time differences
// deducts thatTime from ThisTime and returns a formatted string
clear local
local fn compareTime$( thisTime as str255, thatTime as str255)
dim diffHr   as int
dim diffMn   as int
dim thisTemp as int
dim thatTemp as int
dim myTime   as str255
'
thisTime = fn trad2GMT$( thisTime)
thatTime = fn trad2GMT$( thatTime)
// minutes
thisTemp = val( right$( thisTime,2))
thatTemp = val( right$( thisTime,2))
long if( thatTemp > thisTemp)
diffHr = -1 
thisTemp = thisTemp +60
xelse
diffHr = 0
end if
diffMn = thisTemp - thatTemp
if( diffMn > 59) then diffMn = diffMn -60 : diffHr = diffHr +1
// hours
thisTemp = val( left$( thisTime,2))
thatTemp = val( left$( thisTime,2))
diffHr   = diffHr +( thisTemp - thatTemp)
// format return str$
myTime = str$( diffMn)
myTime = right$( myTime, 2) : if myTime[1] =_" " then mid$( myTime,1,1) =
"0"
myTime = ":" +myTime
myTime = str$( diffHr) +myTime
myTime = right$( myTime, 5) : if myTime[1] =_" " then mid$( myTime,1,1) =
"0"
if( diffHr < 0) then myTime = "-" +myTime else myTime = "+" +myTime
'
end fn = myTime