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timelocal (3)
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(): _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)
GNU 2007-07-26 TIMEGM(3)
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