Fastest timing resolution system

Question

What is the fastest timing system a C/C++ programmer can use?

For example:
time() will give the seconds since Jan 01 1970 00:00.
GetTickCount() on Windows wi

Answer 1

If you're just worried about GetTickCount() overflowing, then you can just wrap it like this:

DWORDLONG GetLongTickCount(void)
{
    static DWORDLONG last_tick = 0;
    DWORD tick = GetTickCount();

    if (tick < (last_tick & 0xffffffff))
        last_tick += 0x100000000;

    last_tick = (last_tick & 0xffffffff00000000) | tick;
    return last_tick;
}

If you want to call this from multiple threads you'll need to lock access to the last_tick variable. As long as you call GetLongTickCount() at least once every 49.7 days, it'll detect the overflow.