[c] Sleep function in Windows, using C

I need to sleep my program in Windows. What header file has the sleep function?

Include the following function at the start of your code, whenever you want to busy wait. This is distinct from sleep, because the process will be utilizing 100% cpu while this function is running.

void sleep(unsigned int mseconds)
{
    clock_t goal = mseconds + clock();
    while (goal > clock())
        ;
}

Note that the name sleep for this function is misleading, since the CPU will not be sleeping at all.

MSDN: Header: Winbase.h (include Windows.h)

SleepEx function (see http://msdn.microsoft.com/en-us/library/ms686307.aspx) is the best choise if your program directly or indirectly creates windows (for example use some COM objects). In the simples cases you can also use Sleep.