Game clock and Sleep (C++) - c++

Question

I'm currently making a small console game. At the end of the game loop is another loop that doesn't release until 1/100s after the iteration's begin time.
Of course that uses up a lot of CPU, so I placed
Sleep(1);
at the end to solve it. I thought everything was right until I ran the game on a 2005 XP laptop... and it was really slow.
When I removed the Sleep command, the game worked perfectly on both computers, but now I have the CPU usage problem.
Does anyone have a good solution for this?

Answer 1

So I found out that the problem was with Windows NT (2000, XP, 2003) sleep granularity that was around 15 ms.. if anyone also struggles with this type of problem, here's how to solve it:
timeBeginPeriod(1); //from windows.h
Call it once at the beginning of the main() function. This affects a few things including Sleep() so that it's actually 'sleeping' for an exact millisecond.
timeEndPeriod(1); //on exit
Of course I was developing the game on Windows 7 all time and thought everything was right, so apparently Windows 6.0+ removed this problem... but it's still useful considering the fact that a lot of people still use XP

Answer 2

You should use std::this_thread::sleep_for in header <thread> for this, along with std::chrono stuff. Maybe something like this:
while(...)
{
auto begin = std::chrono::steady_clock::now();
// your code
auto end = std::chrono::steady_clock::now();
auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin);
std::this_thread::sleep_for(std::chrono::milliseconds(10) - duration);
}
If your code doesn't consume much time during one iteration or if each iteration takes constant time, you can leave alone the measuring and just put there some constant:
std::this_thread::sleep_for(std::chrono::milliseconds(8));

Answer 3

Sounds like the older laptop just takes more time to do all your processes then it sleeps for 1 millisecond.
You should include a library that tells time,
get the current time at the start of the program / start of the loop then at the end of the loop / program compare the difference of your starting time and the current to the amount of time you want. If it's lower than the amount of time you want (let's say 8 milliseconds) tell it to sleep for minimumTime - currentTime - recordedTime (the variable you set at the start of the loop)
I've done this for my own game in SDL2, SDL_GetTicks() just finds the amount of milliseconds the program has been running and "frametime" is the time at the start of the main game loop. This is how I keep my game running at a maximum of 60fps. This if statement should be modified and placed at the bottom of your program.
if( SDL_GetTicks() - frametime < MINFRAMETIME )
{
SDL_Delay( MINFRAMETIME - ( SDL_GetTicks() - frametime ) );
}
I think the standard library equivalent would be:
if( clock() - lastCheck < MIN_TIME )
{
sleep( MIN_TIME - ( clock() - lastCheck ) );
}