newlib-cygwin/newlib/libc/time/gmtime.c

62 lines
1.4 KiB
C

/*
* gmtime.c
* Original Author: G. Haley
*
* Converts the calendar time pointed to by tim_p into a broken-down time
* expressed as Greenwich Mean Time (GMT). Returns a pointer to a structure
* containing the broken-down time, or a null pointer if GMT is not
* available.
*/
/*
FUNCTION
<<gmtime>>---convert time to UTC traditional form
INDEX
gmtime
INDEX
gmtime_r
SYNOPSIS
#include <time.h>
struct tm *gmtime(const time_t *<[clock]>);
struct tm *gmtime_r(const time_t *<[clock]>, struct tm *<[res]>);
DESCRIPTION
<<gmtime>> takes the time at <[clock]> representing the number
of elapsed seconds since 00:00:00 on January 1, 1970, Universal
Coordinated Time (UTC, also known in some countries as GMT,
Greenwich Mean time) and converts it to a <<struct tm>>
representation.
<<gmtime>> constructs the traditional time representation in static
storage; each call to <<gmtime>> or <<localtime>> will overwrite the
information generated by previous calls to either function.
RETURNS
A pointer to the traditional time representation (<<struct tm>>).
PORTABILITY
ANSI C requires <<gmtime>>.
<<gmtime>> requires no supporting OS subroutines.
*/
#include <stdlib.h>
#include <time.h>
#define _GMT_OFFSET 0
#ifndef _REENT_ONLY
struct tm *
gmtime (const time_t * tim_p)
{
struct _reent *reent = _REENT;
_REENT_CHECK_TM(reent);
return gmtime_r (tim_p, (struct tm *)_REENT_TM(reent));
}
#endif