Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>

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timegm, timelocal - inverses for gmtime and localtime

 #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 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() 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)