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(): _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION


The functions timelocal() and timegm() are the inverses of localtime(3) and gmtime(3).

CONFORMING TO


These functions are non-standard GNU extensions that are also present on the BSDs. Avoid their use; see NOTES.

NOTES


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

For a portable version of timegm(), set the TZ environment variable to UTC, call mktime(3) and restore the value of TZ. Something like

#include <time.h> #include <stdlib.h>

time_t my_timegm(struct tm *tm) { time_t ret; char *tz;

tz = getenv("TZ"); setenv("TZ", "", 1); tzset(); ret = mktime(tm); if (tz) setenv("TZ", tz, 1); else unsetenv("TZ"); tzset(); return ret; }

SEE ALSO


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

COLOPHON


This page is part of release 3.23 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

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