offtime_r(3) [netbsd man page]

OFFTIME(3)						   BSD Library Functions Manual 						OFFTIME(3)

NAME

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

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <time.h>

     struct tm *
     offtime(const time_t * clock, long int offset);

     struct tm *
     offtime_r(const time_t * clock, long int offset, struct tm *ret);

     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).

     offtime_r() is similar to offtime() but it places the returned struct tm * in the user supplied ret argument.

     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 func-
     tion mktime(3), and is provided for symmetry only.

SEE ALSO

     ctime(3), tm(3), tzset(3)

BSD
								  April 14, 2011							       BSD

TIMEGM(3)						     Linux Programmer's Manual							 TIMEGM(3)

NAME

       timegm, timelocal - inverses of gmtime and localtime

SYNOPSIS

       #include <time.h>

       time_t timelocal(struct tm *tm);

       time_t timegm(struct tm *tm);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       timelocal(), timegm():
	   Since glibc 2.19:
	       _DEFAULT_SOURCE
	   Glibc 2.19 and earlier:
	       _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

       The  functions timelocal() and timegm() are the inverses of localtime(3) and gmtime(3).	Both functions take a broken-down time and convert
       it to calendar time (seconds since the Epoch, 1970-01-01 00:00:00 +0000, UTC).  The difference between the two functions  is  that  timelo-
       cal()  takes  the  local  timezone into account when doing the conversion, while timegm() takes the input value to be Coordinated Universal
       Time (UTC).

RETURN VALUE

       On success, these functions return the calendar time (seconds since the Epoch), expressed as a value of type time_t.  On error, they return
       the value (time_t) -1 and set errno to indicate the cause of the error.

ERRORS

       EOVERFLOW
	      The result cannot be represented.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +----------------------+---------------+--------------------+
       |Interface	      | Attribute     | Value		   |
       +----------------------+---------------+--------------------+
       |timelocal(), timegm() | Thread safety | MT-Safe env locale |
       +----------------------+---------------+--------------------+
CONFORMING TO

       These functions are nonstandard GNU extensions that are also present on the BSDs.  Avoid their use.

NOTES

       The timelocal() function is equivalent to the POSIX standard function mktime(3).  There is no reason to ever use it.

SEE ALSO

       gmtime(3), localtime(3), mktime(3), tzset(3)

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU
								    2016-12-12								 TIMEGM(3)