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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
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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
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 5.13 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 2021-03-22 TIMEGM(3)
Pages that refer to this page: ctime(3)
Copyright and license for this manual page
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