May 10, 2004 OFFTIME 3

### NAME

offtime, timeoff, timegm, timelocal - convert date and time

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```struct` `tm``*` offtime(```const time_t * clock``, long int offset`)
```time_t` timeoff(```struct tm * tm``, long int offset`)
```time_t` timegm(```struct tm * tm`)
```time_t` timelocal(```struct tm * tm`)

### DESCRIPTION

These functions are inspired by C standard interfaces named similarly.

offtime(``) converts the calendar time ```clock`, offset by ```offset` seconds, into broken-down time, expressed as Coordinated Universal Time (UTC).

timeoff(``) converts the broken-down time ```tm`, expressed as UTC, offset by ```offset` seconds, into a calendar time value.

timegm(``) converts the broken-down time ```tm` into a calendar time value, effectively being the inverse of gmtime(3). It is equivalent to the C standard function mktime(3) operating in UTC.

timelocal(``) converts the broken down time ```tm`, expressed as local time, into a calendar time value. It is equivalent to the C standard function mktime(3), and is provided for symmetry only.

### SEE ALSO

ctime(3), tzset(3)