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Getting time from system clock in nanoseconds

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Getting time from system clock in nanoseconds

Oct 27th, 2004

How can i get the time from the system clock in nanoseconds??
im using c++ here..
thanx..

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Re: Getting time from system clock in nanoseconds

Oct 27th, 2004

On Windows, you can get the number of milliseconds since the processor started (GetTickCount()), and there are 'high resolution timers' (see "multimedia timer" or "high resolution timer" in VC help) that are higher resolution than that, but you won't get an accurate number of nanoseconds.

Besides, by the time the light traveled from your screen to your eyeball, the time in nanoseconds would be out-of-date. :-)

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Re: Getting time from system clock in nanoseconds

Aug 5th, 2008

How can i get tha system boot time.plz provide me solution with code.
i want time in usec from system booted

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Re: Getting time from system clock in nanoseconds

Aug 5th, 2008

system boot time is the value returned by GetTickCount(). If you want to know the actual date/time, call time() function in time.h, then localtime() to get struct tm pointer. From that subtract the number of seconds returned by GetTickCount(), pass that result to mktime() (from time.h) which will do all the math needed to normalize the date/time in struct tm. Volla -- you have the actual date/time the system was booted.

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Re: Getting time from system clock in nanoseconds

Aug 5th, 2008

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <iomanip>
#include <ctime>
#include <windows.h>
using namespace std;
 
 
int main()
{
    DWORD ticks = GetTickCount() / 1000;
    cout << ticks << "\n";
    time_t now = time(0);
    struct tm* tm = localtime(&now);
    tm->tm_sec -= ticks;
    now = mktime(tm);
    cout << setw(2) << setfill('0') << tm->tm_mon << ":" << setw(2) << setfill('0') << 
        tm->tm_mday << ":" << setw(4) <<tm->tm_year + 1900 << "  ";
    cout << setw(2) << setfill('0') << tm->tm_hour << "/" << 
        setw(2) << setfill('0') << tm->tm_min << "/" << setw(2) << setfill('0') << tm->tm_sec << "\n";
 
}
#include <iostream>
#include <iomanip>
#include <ctime>
#include <windows.h>
using namespace std;


int main()
{
    DWORD ticks = GetTickCount() / 1000;
    cout << ticks << "\n";
    time_t now = time(0);
    struct tm* tm = localtime(&now);
    tm->tm_sec -= ticks;
    now = mktime(tm);
    cout << setw(2) << setfill('0') << tm->tm_mon << ":" << setw(2) << setfill('0') << 
        tm->tm_mday << ":" << setw(4) <<tm->tm_year + 1900 << "  ";
    cout << setw(2) << setfill('0') << tm->tm_hour << "/" << 
        setw(2) << setfill('0') << tm->tm_min << "/" << setw(2) << setfill('0') << tm->tm_sec << "\n";

}

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Re: Getting time from system clock in nanoseconds

Aug 5th, 2008

Wow, a 4 year bump, and the answer is still the same?
Did the bumper bother to read anything, or just attach the same question based on the result of a feeble search?

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brain

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Re: Getting time from system clock in nanoseconds

-1

Sep 2nd, 2008

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Originally Posted by Ancient Dragon

Help with Code Tags

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <iomanip>
#include <ctime>
#include <windows.h>
using namespace std;
 
 
int main()
{
    DWORD ticks = GetTickCount() / 1000;
    cout << ticks << "\n";
    time_t now = time(0);
    struct tm* tm = localtime(&now);
    tm->tm_sec -= ticks;
    now = mktime(tm);
    cout << setw(2) << setfill('0') << tm->tm_mon << ":" << setw(2) << setfill('0') << 
        tm->tm_mday << ":" << setw(4) <<tm->tm_year + 1900 << "  ";
    cout << setw(2) << setfill('0') << tm->tm_hour << "/" << 
        setw(2) << setfill('0') << tm->tm_min << "/" << setw(2) << setfill('0') << tm->tm_sec << "\n";
 
}
#include <iostream> #include <iomanip> #include <ctime> #include <windows.h> using namespace std; int main() { DWORD ticks = GetTickCount() / 1000; cout << ticks << "\n"; time_t now = time(0); struct tm* tm = localtime(&now); tm->tm_sec -= ticks; now = mktime(tm); cout << setw(2) << setfill('0') << tm->tm_mon << ":" << setw(2) << setfill('0') << tm->tm_mday << ":" << setw(4) <<tm->tm_year + 1900 << " "; cout << setw(2) << setfill('0') << tm->tm_hour << "/" << setw(2) << setfill('0') << tm->tm_min << "/" << setw(2) << setfill('0') << tm->tm_sec << "\n"; }