Determines the local time bias from UTC that was in force at a specified time. For example, US Pacific Standard Time is -8 hrs from UTC, so -28800 would be returned (-8 hours x 60 minutes x 60 seconds). However, if the specified time occurred during daylight saving, the returned value would be -7 hours (or -25200 seconds).
The time/date variable.
The local time bias in seconds.