Getting Windows system time in C++

[Kamikaze Badger]

As the title says, how do you get the system time in C++ on Windows? And putting it into a variable would be the same as any other typecasting thing, right?

[White Scorpion]

GetSystemTime
or
GetLocalTime

these are both API's which can be used to get the time. they are different so i suggest you take a read through those links to determine which one suits your purpose

[whizkid2300]

You could always do a system call. And get the output from that.

[;TT]

system("time");

[whizkid2300]

I wasn't asking how to, I was saying that she/he could.

[White Scorpion]

that's true, but it will be a lot harder to calculate with and the API's are a lot more powerful.

system("time");

this doesn't work under windows, since it WILL display the time, but at the same time asks you for the new time

[sec_ware]

Hi

I am wondering about that question. Doing a google using "Windows system time in C++"
provides you with the links you need - fully documented. One interesting ingredient here is
the remark about using the API's by White Scorpion.

system-call

You can read the system time without being prompted for a new time using
system("time /T"); but on depending what you want to do with the time, this is
a bad option.

high resolution

If you wish to do high-resolution time measurements there is a possiblity
to use the system clock. Around 10 years ago, this provided you with
a resolution of 1/4096 secs per tic (or so...). Nowadays I don't know. Somewhere at
home, I even might have a code of mine using this ( in Pascal/ASM, as far as I remember).

time.h, timeb.h

Here is a an excerpt that is slightly modified by myself of Times.C by the MSDN Library
(publicly available [1])

#include <time.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/timeb.h>
#include <string.h>

void main()
{


// MSDN Library TIMES.C

    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( &ltime );
    printf( "Time in seconds since UTC 1/1/70:\t%ld\n", ltime );
    printf( "UNIX time and date:\t\t\t%s", ctime( &ltime ) );

    /* Display UTC. */
    gmt = gmtime( &ltime );
    printf( "Coordinated universal time:\t\t%s", asctime( gmt ) );

    /* Convert to time structure and adjust for PM if necessary. */
    today = localtime( &ltime );
    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( &ltime );

    /* 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 );
}

I hope this answers your question fully and you can use 1-1 the examples.



Cheers!

[1] http://msdn.microsoft.com/library/de..._.wcsftime.asp