GMTIME(P)						     POSIX Programmer's Manual							 GMTIME(P)

NAME

       gmtime, gmtime_r - convert a time value to a broken-down UTC time

SYNOPSIS

       #include <time.h>

       struct tm *gmtime(const time_t *timer);

       struct tm *gmtime_r(const time_t *restrict timer,
	      struct tm *restrict result);

DESCRIPTION

       For  gmtime():	 The  functionality described on this reference page is aligned with the ISO C standard. Any conflict between the require-
       ments described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard.

       The gmtime() function shall convert the time in seconds since the Epoch pointed to by timer into a broken-down time, expressed  as  Coordi-
       nated Universal Time (UTC).

       The  relationship  between  a time in seconds since the Epoch used as an argument to gmtime() and the tm structure (defined in the <time.h>
       header) is that the result shall be as specified in the expression given in the definition of seconds since the Epoch (see the Base Defini-
       tions volume of IEEE Std 1003.1-2001, Section 4.14, Seconds Since the Epoch), where the names in the structure and in the expression corre-
       spond.

       The same relationship shall apply for gmtime_r().

       The gmtime() function need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.

       The asctime(), ctime(), gmtime(), and localtime() functions shall return values in one of two static objects: a broken-down time  structure
       and  an	array  of type char. Execution of any of the functions may overwrite the information returned in either of these objects by any of
       the other functions.

       The gmtime_r() function shall convert the time in seconds since the Epoch pointed to by timer into a broken-down time expressed as  Coordi-
       nated  Universal  Time  (UTC).  The  broken-down  time is stored in the structure referred to by result. The gmtime_r() function shall also
       return the address of the same structure.

RETURN VALUE

       Upon successful completion, the gmtime() function shall return a pointer to a struct tm. If an error is detected, gmtime() shall  return  a
       null pointer    and set errno to indicate the error.

       Upon  successful  completion,  gmtime_r()  shall  return  the  address  of the structure pointed to by the argument result.  If an error is
       detected, gmtime_r() shall return a null pointer.

ERRORS

       The gmtime() function shall fail if:

       EOVERFLOW
	      The result cannot be represented.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The gmtime_r() function is thread-safe and returns values in a user-supplied buffer instead of possibly using a static data area  that  may
       be overwritten by each call.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       asctime()  ,  clock()  ,  ctime() , difftime() , localtime() , mktime() , strftime() , strptime() , time() , utime() , the Base Definitions
       volume of IEEE Std 1003.1-2001, <time.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								 GMTIME(P)