1.\" $NetBSD: offtime.3,v 1.3 2011/04/14 05:50:50 jruoho Exp $ 2.\" Written by Klaus Klein, May 10, 2004. 3.\" Public domain. 4.Dd April 14, 2011 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 struct tm * 20.Fn offtime_r "const time_t * clock" "long int offset" "struct tm *ret" 21.Ft time_t 22.Fn timeoff "struct tm * tm" "long int offset" 23.Ft time_t 24.Fn timegm "struct tm * tm" 25.Ft time_t 26.Fn timelocal "struct tm * tm" 27.Sh DESCRIPTION 28These functions are inspired by C standard interfaces named similarly. 29.Pp 30.Fn offtime 31converts the calendar time 32.Fa clock , 33offset by 34.Fa offset 35seconds, 36into broken-down time, expressed as Coordinated Universal Time (UTC). 37.Pp 38.Fn offtime_r 39is similar to 40.Fn offtime 41but it places the returned 42.Ft "struct tm *" 43in the user supplied 44.Fa ret 45argument. 46.Pp 47.Fn timeoff 48converts the broken-down time 49.Fa tm , 50expressed as UTC, 51offset by 52.Fa offset 53seconds, 54into a calendar time value. 55.Pp 56.Fn timegm 57converts the broken-down time 58.Fa tm 59into a calendar time value, effectively being the inverse of 60.Xr gmtime 3 . 61It is equivalent to the C standard function 62.Xr mktime 3 63operating in UTC. 64.Pp 65.Fn timelocal 66converts the broken down time 67.Fa tm , 68expressed as local time, into a calendar time value. 69It is equivalent to the C standard function 70.Xr mktime 3 , 71and is provided for symmetry only. 72.Sh SEE ALSO 73.Xr ctime 3 , 74.Xr tm 3 , 75.Xr tzset 3 76