TIMEGM(3) Linux Programmer's Manual TIMEGM(3)NAME
timegm, timelocal - inverses for gmtime and localtime
SYNOPSIS
#include <time.h>
time_t timelocal (struct tm *tm);
time_t timegm (struct tm *tm);
DESCRIPTION
The functions timelocal() and timegm() are the inverses to localtime(3)
and gmtime(3).
NOTES
These functions are GNU extensions. The timelocal() function is equiv‐
alent 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() 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;
}
CONFORMING TO
Not in POSIX.1-2001. Present on the BSDs.
SEE ALSOgmtime(3), localtime(3), mktime(3), tzset(3)GNU 2001-12-26 TIMEGM(3)
