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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
TIMEGM(3) Linux Programmer's Manual TIMEGM(3)
timegm, timelocal - inverses of gmtime and localtime
#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
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 timelocal() takes the local timezone into account when doing the
conversion, while timegm() takes the input value to be Coordinated
Universal Time (UTC).
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.
EOVERFLOW
The result cannot be represented.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────┬───────────────┬────────────────────┐
│Interface │ Attribute │ Value │
├──────────────────────┼───────────────┼────────────────────┤
│timelocal(), timegm() │ Thread safety │ MT-Safe env locale │
└──────────────────────┴───────────────┴────────────────────┘
These functions are nonstandard GNU extensions that are also present
on the BSDs. Avoid their use.
The timelocal() function is equivalent to the POSIX standard function
mktime(3). There is no reason to ever use it.
gmtime(3), localtime(3), mktime(3), tzset(3)
This page is part of release 4.12 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)
Pages that refer to this page: ctime(3)