time
Gets the system time.
time_ttime(time_t*timer);
| Routine | Required Header | Compatibility |
| time | <time.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
time returns the time in elapsed seconds. There is no error return.
Parameter
timer
Storage location for time
Remarks
The time function returns the number of seconds elapsed since midnight (00:00:00), January 1, 1970, coordinated universal time, according to the system clock. The return value is stored in the location given by timer. This parameter may be NULL, in which case the return value is not stored.
Example
/* TIMES.C illustrates various time and date functions including:
* time _ftime ctime asctime
* localtime gmtime mktime _tzset
* _strtime _strdate strftime
* Also the global variable:
* _tzname
*/
#include <time.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/timeb.h>
#include <string.h>
void main()
{
char tmpbuf[128], ampm[] = "AM";
time_t ltime;
struct _timeb tstruct;
struct tm *today, *gmt, xmas = { 0, 0, 12, 25, 11, 93 };
/* Set time zone from TZ environment variable. If TZ is not set,
* the operating system is queried to obtain the default value
* for the variable.
*/
_tzset();
/* Display operating system-style date and time. */
_strtime( tmpbuf );
printf( "OS time:\t\t\t\t%s\n", tmpbuf );
_strdate( tmpbuf );
printf( "OS date:\t\t\t\t%s\n", tmpbuf );
/* Get UNIX-style time and display as number and string. */
time( <ime );
printf( "Time in seconds since UTC 1/1/70:\t%ld\n", ltime );
printf( "UNIX time and date:\t\t\t%s", ctime( <ime ) );
/* Display UTC. */
gmt = gmtime( <ime );
printf( "Coordinated universal time:\t\t%s", asctime( gmt ) );
/* Convert to time structure and adjust for PM if necessary. */
today = localtime( <ime );
if( today->tm_hour > 12 )
{
strcpy( ampm, "PM" );
today->tm_hour -= 12;
}
if( today->tm_hour == 0 ) /* Adjust if midnight hour. */
today->tm_hour = 12;
/* Note how pointer addition is used to skip the first 11
* characters and printf is used to trim off terminating
* characters.
*/
printf( "12-hour time:\t\t\t\t%.8s %s\n",
asctime( today ) + 11, ampm );
/* Print additional time information. */
_ftime( &tstruct );
printf( "Plus milliseconds:\t\t\t%u\n", tstruct.millitm );
printf( "Zone difference in seconds from UTC:\t%u\n",
tstruct.timezone );
printf( "Time zone name:\t\t\t\t%s\n", _tzname[0] );
printf( "Daylight savings:\t\t\t%s\n",
tstruct.dstflag ? "YES" : "NO" );
/* Make time for noon on Christmas, 1993. */
if( mktime( &xmas ) != (time_t)-1 )
printf( "Christmas\t\t\t\t%s\n", asctime( &xmas ) );
/* Use time structure to build a customized time string. */
today = localtime( <ime );
/* Use strftime to build a customized time string. */
strftime( tmpbuf, 128,
"Today is %A, day %d of %B in the year %Y.\n", today );
printf( tmpbuf );
}
Output
OS time: 21:51:03
OS date: 05/03/94
Time in seconds since UTC 1/1/70: 768027063
UNIX time and date: Tue May 03 21:51:03 1994
Coordinated universal time: Wed May 04 04:51:03 1994
12-hour time: 09:51:03 PM
Plus milliseconds: 279
Zone difference in seconds from UTC: 480
Time zone name:
Daylight savings: YES
Christmas Sat Dec 25 12:00:00 1993
Today is Tuesday, day 03 of May in the year 1994.