Hi Paul,

PowerBuilder has no system functions to do time interval calculations. Neither does PFC. I just checked PFC for PB 2017 including the DateTime service.

Basically, you need two functions:

• CalculateOverlap: returns the overlap[start; stop] between time intervals A[start; stop] and B[start; stop] using DateTime for all Start and Stop points in time
• HoursAfter: returns the distance between Start and Stop DateTimes measured in hours
• - OR - mix the two functions into one, e.g. CalculateOverlapHours. and thereby violate the single responsibility pricinple

Notes on prerequisites for calculating such intervals and durations:

• You must use DateTime instead of Time to avoid issues across midnight and for duration > 24 hours
• You must decide whether to ignore time zones or how to handle (EX: Convert to UTC)
• You must decide whether to ignore start/end daylight savings time or how to handle (EX: Convert to UTC)
• You must decide whether to ignore "leap seconds" or how to handle (EX: Convert to TAI {aka. Atomic Time} instead of UTC)

HTH /Michael

see: SecondsAfter ( time1, time2 )

then divide the seconds to get  hours