gmtime() — Convert Time

Format 

#include <time.h>
struct tm *gmtime(const time_t *time);

Language Level: ANSI

Threadsafe: No. Use gmtime_r() instead.

Description

The gmtime() function breaks down the time value, in seconds, and stores it in a tm structure, defined in <time.h>. The value time is usually obtained by a call to the time() function.

The fields of the tm structure include:

tm_sec
Seconds (0-61)
tm_min
Minutes (0-59)
tm_hour
Hours (0-23)
tm_mday
Day of month (1-31)
tm_mon
Month (0-11; January = 0)
tm_year
Year (current year minus 1900)
tm_wday
Day of week (0-6; Sunday = 0)
tm_yday
Day of year (0-365; January 1 = 0)
tm_isdst
Zero if daylight saving time is not in effect; positive if daylight saving time is in effect; negative if the information is not available.

Return Value

The gmtime() function returns a pointer to the resulting tm structure.

Notes:
  1. The range (0-61) for tm_sec allows for as many as two leap seconds.
  2. The gmtime() and localtime() functions can use a common, statically allocated buffer for the conversion. Each call to one of these functions might alter the result of the previous call.
  3. Calendar time is the number of seconds that have elapsed since EPOCH, which is 00:00:00, January 1, 1970 Universal Coordinate Time (UTC).

Example that uses gmtime()

This example uses the gmtime() function to adjust a time_t representation to a Coordinated Universal Time character string, and then converts it to a printable string using the asctime() function. 

#include <stdio.h>
#include <time.h>
 
int main(void)
{
   time_t ltime;
 
      time(&ltime);
		printf ("Coordinated Universal Time is %s\n",
            asctime(gmtime(&ltime)));
}
 
/************************  Output should be similar to:  **********
 
Coordinated Universal Time is Wed Aug 18 21:01:44 1993
*/

Related Information


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