线程的优先级

1.      每个线程都有一个优先级，取值为0~31；

2.      Windows调度线程的原则：只要高优先级的进程可调度，就不会为低优先级的线程分配CPU;

3.      线程的相对优先级就是线程的真实优先级，与其所在的进程优先级无关。

4.      要改变线程的优先级，要调用函数：

BOOL WINAPI SetThreadPriority(   __in   HANDLE hThread,   __in  int  nPriority );

程序实例：

#include "stdafx.h"

DWORD WINAPI ThreadProc1(LPVOID lpParam)
{
	for(int i = 0;i < 10;i++)
		cout << "Idle Thread is running"<<endl;
	return 0;
}

DWORD WINAPI ThreadProc2(LPVOID lpParam)
{
	for(int i = 0;i < 10;i++)
		cout << "Normal Thread is running"<<endl;
	return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
	HANDLE h[2];
	DWORD  dwThreadID[2];
	h[0] = ::CreateThread(NULL,NULL,ThreadProc1,NULL,CREATE_SUSPENDED,&dwThreadID[0]);
	h[1] = ::CreateThread(NULL,NULL,ThreadProc2,NULL,CREATE_SUSPENDED,&dwThreadID[0]);
	::SetThreadPriority(h[0],THREAD_PRIORITY_IDLE);
	::ResumeThread(h[0]);
	::ResumeThread(h[1]);

	::WaitForMultipleObjects(2,h,TRUE,INFINITE);

	system("pause");
	return 0;
}