TIMEGM(3)		   Linux Programmers Manual		    TIMEGM(3)



NAME
       timegm, timelocal - inverses of gmtime and localtime

SYNOPSIS
       #include 

       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 
	   #include 

	   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 3.05 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/.



GNU				  2007-07-26			     TIMEGM(3)