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;
}
SEE ALSO
gmtime(3), localtime(3), mktime(3), tzset(3)
GNU 2001-12-26 timegm(3)
Mac OS X 10.8 - Generated Fri Aug 31 16:05:38 CDT 2012