// crt_times.c
// compile with: /W3
// This program demonstrates these time and date functions:
// time _ftime ctime_s asctime_s
// _localtime64_s _gmtime64_s mktime _tzset
// _strtime_s _strdate_s strftime
//
// Also the global variable:
// _tzname
//
#include <time.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/timeb.h>
#include <string.h>
int main()
{
char tmpbuf[128], timebuf[26], ampm[] = "AM";
time_t ltime;
struct _timeb tstruct;
struct tm today, gmt, xmas = { 0, 0, 12, 25, 11, 93 };
errno_t err;
// 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_s( tmpbuf, 128 );
printf( "OS time:\t\t\t\t%s\n", tmpbuf );
_strdate_s( tmpbuf, 128 );
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 );
err = ctime_s(timebuf, 26, <ime);
if (err)
{
printf("ctime_s failed due to an invalid argument.");
exit(1);
}
printf( "UNIX time and date:\t\t\t%s", timebuf );
// Display UTC.
err = _gmtime64_s( &gmt, <ime );
if (err)
{
printf("_gmtime64_s failed due to an invalid argument.");
}
err = asctime_s(timebuf, 26, &gmt);
if (err)
{
printf("asctime_s failed due to an invalid argument.");
exit(1);
}
printf( "Coordinated universal time:\t\t%s", timebuf );
// Convert to time structure and adjust for PM if necessary.
err = _localtime64_s( &today, <ime );
if (err)
{
printf("_localtime64_s failed due to an invalid argument.");
exit(1);
}
if( today.tm_hour >= 12 )
{
strcpy_s( ampm, sizeof(ampm), "PM" );
today.tm_hour -= 12;
}
if( today.tm_hour == 0 ) // Adjust if midnight hour.
today.tm_hour = 12;
// Convert today into an ASCII string
err = asctime_s(timebuf, 26, &today);
if (err)
{
printf("asctime_s failed due to an invalid argument.");
exit(1);
}
// 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",
timebuf + 11, ampm );
// Print additional time information.
_ftime( &tstruct ); // C4996
// Note: _ftime is deprecated; consider using _ftime_s instead
printf( "Plus milliseconds:\t\t\t%u\n", tstruct.millitm );
printf( "Zone difference in hours from UTC:\t%u\n",
tstruct.timezone/60 );
printf( "Time zone name:\t\t\t\t%s\n", _tzname[0] ); //C4996
// Note: _tzname is deprecated; consider using _get_tzname
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 )
{
err = asctime_s(timebuf, 26, &xmas);
if (err)
{
printf("asctime_s failed due to an invalid argument.");
exit(1);
}
printf( "Christmas\t\t\t\t%s\n", timebuf );
}
// Use time structure to build a customized time string.
err = _localtime64_s( &today, <ime );
if (err)
{
printf(" _localtime64_s failed due to invalid arguments.");
exit(1);
}
// 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 );
}