C++ Win32 Delta Time

#include <Windows.h>
#include <iostream>
#include <string>

using namespace std;

//internal variables
long double lastMilliseconds = 0.0;
long double deltatime = 0.0;
unsigned int limit = 0;

//function prototypes
void SetDeltaTime();
unsigned int FPSLimit(int targetFPS);
DWORD CALLBACK Display(LPVOID parameter);
DWORD CALLBACK CalcDelta(LPVOID parameter);
DWORD CALLBACK MessageProc(LPVOID parameter);

BOOL main(int argc, char* argv[]) {
    int fps = 0;
    if (argc > 1) { //if a number is passed, set the FPS limit to it
        fps = strtol(argv[1], 0, 0);
    }
    limit = FPSLimit(fps);

    CreateThread(0, 0, CalcDelta, 0, 0, 0); //create thread to calculate the delta time
    CreateThread(0, 0, Display, 0, 0, 0); //create thread to display the FPS

    MSG msg; //hold windows messages here
    while (msg.message != WM_QUIT) {
        while (PeekMessage(&msg, 0, 0, 0, PM_REMOVE)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
    return FALSE;
}

void SetDeltaTime() {
    SYSTEMTIME time;
    GetSystemTime(&time);
    long double milliseconds = (time.wSecond * 1000.0) + time.wMilliseconds;
    deltatime = (milliseconds - lastMilliseconds) * 0.001;
    lastMilliseconds = milliseconds;
}

unsigned int FPSLimit(int targetFPS) {
    return (unsigned int)(1.0 / (long double)targetFPS * 1000.0);
}

DWORD CALLBACK Display(LPVOID parameter) {
    while (true) {
        Sleep(1000);
        //unsigned long long was required because otherwise it just displayed infinite with the FPS uncapped
        cout << (unsigned long long int)(1.0 / deltatime) << endl;
    }
    return 1;
}

DWORD CALLBACK CalcDelta(LPVOID parameter) {
    while (true) {
        Sleep(limit);
        SetDeltaTime();
    }
    return 1;
}