1.\" $NetBSD: offtime.3,v 1.1 2004/05/10 02:02:00 kleink Exp $ 2.\" Written by Klaus Klein, May 10, 2004. 3.\" Public domain. 4.Dd May 10, 2004 5.Dt OFFTIME 3 6.Os 7.Sh NAME 8.Nm offtime , 9.Nm timeoff , 10.Nm timegm , 11.Nm timelocal 12.Nd convert date and time 13.Sh LIBRARY 14.Lb libc 15.Sh SYNOPSIS 16.In time.h 17.Ft struct tm * 18.Fn offtime "const time_t * clock" "long int offset" 19.Ft time_t 20.Fn timeoff "struct tm * tm" "long int offset" 21.Ft time_t 22.Fn timegm "struct tm * tm" 23.Ft time_t 24.Fn timelocal "struct tm * tm" 25.Sh DESCRIPTION 26These functions are inspired by C standard interfaces named similarly. 27.Pp 28.Fn offtime 29converts the calendar time 30.Fa clock , 31offset by 32.Fa offset 33seconds, 34into broken-down time, expressed as Coordinated Universal Time (UTC). 35.Pp 36.Fn timeoff 37converts the broken-down time 38.Fa tm , 39expressed as UTC, 40offset by 41.Fa offset 42seconds, 43into a calendar time value. 44.Pp 45.Fn timegm 46converts the broken-down time 47.Fa tm 48into a calendar time value, effectively being the inverse of 49.Xr gmtime 3 . 50It is equivalent to the C standard function 51.Xr mktime 3 52operating in UTC. 53.Pp 54.Fn timelocal 55converts the broken down time 56.Fa tm , 57expressed as local time, into a calendar time value. 58It is equivalent to the C standard function 59.Xr mktime 3 , 60and is provided for symmetry only. 61.Sh SEE ALSO 62.Xr ctime 3 , 63.Xr tzset 3 64