SAS/C Library Reference, Vol. 1

gmtime -- Break Greenwich Mean Time into Components

SYNOPSIS


 #include <time.h>

 struct tm *gmtime(const time_t *timep);

DESCRIPTION

gmtime converts a time_t value to Greenwich Mean Time (GMT), separates it into components and returns a pointer to a struct tm containing the results.

RETURN VALUE

gmtime returns a pointer to the broken-down GMT value. The pointer may be to static data, which may remain valid only until the next call to gmtime, localtime, or ctime.

CAUTIONS

The pointer returned by gmtime may reference static storage, which may be overwritten by the next call to gmtime, localtime, or ctime.

gmtime assumes that the value stored in the hardware time-of-day clock is GMT, as specified by 370 standards. If your site uses the time-of-day clock for local time, then gmtime returns local time, not Greenwich time, and Greenwich time is unavailable.

DIAGNOSTICS

NULL is returned if GMT is not available or if the argument value is not a valid time.

EXAMPLE

  #include <time.h>
  #include <stdio.h>

  main ()
  {
     time_t timeval;
     struct tm *now;

     time(&timeval);
     now = gmtime(&timeval);  /* Get current GMT time. */
     if (now->tm_mon == 11 && now->tm_mday == 25)
        puts("Merry Christmas.");
  }

RELATED FUNCTIONS

localtime