c++ winapi 多线程通信之事件机制

功能介绍

本次作业实现了使用event事件机制进行线程间通信控制，控制两个子进程实现1到100000的累加，第一个子进程thread1负责偶数的累加，第二个子进程thread2负责基数的累加，最终得出计算结果为5000050000，经过res函数验证结果正确。

实现代码 c++

#include<Windows.h>
#include<iostream>
#include<string>
using namespace std;
long long sum = 0;
int maxn = 100000;
CRITICAL_SECTION cs;
DWORD WINAPI thread1(PVOID pvParam) {
    //进入临界区后进行屏幕输出，防止两个线程同时输出导致输出混乱
	EnterCriticalSection(&cs);
	cout << "Threat1 is running!" << endl;
	LeaveCriticalSection(&cs);
	//打开event1事件
	HANDLE hEvent = OpenEvent(EVENT_ALL_ACCESS, TRUE, TEXT("event1"));
	for (int i = 0; i <= maxn; i += 2) {
		//等待event1为受信状态后向下执行
		WaitForSingleObject(hEvent, INFINITE);
		//cout << "hevent1 is true" << endl;
		//设置event1 为未受信状态，防止其他线程操作
		//ResetEvent(hEvent);
		sum += i;
		//操作结束后更改event1为受信状态，允许其他子线程访问
		SetEvent(hEvent);
	}
	return 0;
}
DWORD WINAPI thread2(PVOID pvParam) {
	EnterCriticalSection(&cs);
	cout << "Threat2 is running!" << endl;
	LeaveCriticalSection(&cs);
	HANDLE hEvent = OpenEvent(EVENT_ALL_ACCESS, TRUE, TEXT("event1"));
	for (int i = 1; i <= maxn; i += 2) {
		WaitForSingleObject(hEvent, INFINITE);
		//ResetEvent(hEvent);
		sum += i;
		SetEvent(hEvent);
	}
	return 0;
}
long long res() {
	long long s = 0;
	for (int i = 1; i <= maxn; i++) {
		s += i;
	}
	return s;
}
int main() {
	InitializeCriticalSection(&cs);
	//创建事件event1
	HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, TEXT("event1"));
	//CreateEvent()参数分别表示安全属性、人工重置选项、初始受信状态、对象名，第二个False表示不使用人工重置即自动重置，在event被获取到后（WaitForSingleObject）自动变为未受信状态，不需要使用ResetEvent进行状态变更
	//text（）作用是实现对字符处理的透明化，不论是否使用 unicode 字符集，使用 TEXT 宏都可以使程序正常使用，
	//如果程序中有 unicode 宏的，那么就使用宽字符，否则使用单字节字符，保证程序的可移植性
	cout << "event1 was created and fIinitialState is False \n";
	//设置event1事件为受信状态
	SetEvent(hEvent);
	//创建子进程threat1和threat2
	HANDLE hThreat1 = CreateThread(NULL, 0, thread1, NULL, 0, NULL);
	HANDLE hThreat2 = CreateThread(NULL, 0, thread2, NULL, 0, NULL);
	EnterCriticalSection(&cs);
	cout << "threat1 and threat2 were created!\n";
	LeaveCriticalSection(&cs);

	//ResumeThread(hThreat1);
	//ResumeThread(hThreat1);
	HANDLE hThreats[2] = { hThreat1,hThreat2 };
	WaitForMultipleObjects(2, hThreats, TRUE, INFINITE);
	cout << "Mutil threats result of the sum from 1 to "<<maxn<<" is " << sum << endl;
	cout << "Right result of the sum from 1 to " << maxn << " is " << res() << endl;
	return 0;
}