Question

I’m trying to get this accurate timer working on VS2008, on Windows XP (and eventually Server 2008) from the following example:

http://technology.chtsai.org/w98timer/

However I get the following errors:

• error LNK2019: unresolved external symbol _imp_timeEndPeriod@4
• error LNK2019: unresolved external symbol _imp_timeGetTime@0
• error LNK2019: unresolved external symbol _imp_timeBeginPeriod@4
• error LNK2019: unresolved external symbol _imp_timeGetDevCaps@8

Could anybody please advise?

I just want a simple, accurate, millisecond-timing example for C++ on Windows.

#include <stdio.h>
#include <windows.h>
#include <mmsystem.h>
#include "stdafx.h"

void 
main (void)
{
  TIMECAPS resolution;
  DWORD start, finish, duration, i;

  if (timeGetDevCaps (&resolution, sizeof (TIMECAPS)) == TIMERR_NOERROR)
    {
      printf ("Minimum supported resolution = %d\n", resolution.wPeriodMin);
      printf ("Maximum supported resolution = %d\n", resolution.wPeriodMax);
    }

  if (resolution.wPeriodMin <= 1)
    {
      if (timeBeginPeriod (1) == TIMERR_NOERROR)
    {
      for (i = 100; i <= 120; i++)
        {
          start = timeGetTime ();
          while (timeGetTime () < (start + i));
          finish = timeGetTime ();
          duration = finish - start;
          printf ("expected:%d  actual:%ld\n", i, duration);
        }
      timeEndPeriod (1);
    }
    }
}

Answer 1

As MSDN suggests you need to include winmm.lib into the project. So add the following line anywhere into your source code:

#pragma comment(lib, "winmm.lib")