2021-05-07

最新推荐文章于 2022-04-04 18:26:11 发布

原创最新推荐文章于 2022-04-04 18:26:11 发布 · 95 阅读

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这段代码展示了在Windows环境下使用C++实现多线程同步的示例，通过互斥事件和临界区进行线程间通信。每个线程按顺序在共享字符串中插入字符，最终打印出结果。

#include <windows.h>
#include <process.h>
#include "stdio.h"
#include <iostream>
using namespace std;
 
const int THREAD_NUM = 4;
HANDLE g_ThreadEvent[THREAD_NUM];
HANDLE g_OK;
 
unsigned int __stdcall Fun(void *pPM);
 
string g_write;
//int g_index = 0;
 
CRITICAL_SECTION g_cs;
int g_loop = 1;
void StartThread();
int main()
{
	int innum=4;
	while (cin>>innum)
	{
		g_loop = innum;
		StartThread();
		g_write.clear();
	}
	
 
	return 0;
}
 
void StartThread()
{
	InitializeCriticalSection(&g_cs);
	//1.创建互斥事件
	for (int i = 0; i < THREAD_NUM; i++)
	{
		g_ThreadEvent[i] = CreateEvent(NULL, FALSE, FALSE, NULL);
	}
	g_OK = CreateEvent(NULL, FALSE, FALSE, NULL);
	//2.创建线程
	HANDLE hdl[THREAD_NUM];
 
	for (int i = 0; i < THREAD_NUM; i++)
	{
		hdl[i] = (HANDLE)_beginthreadex(NULL, 0, Fun, (void*)i, 0, NULL);
	}
 
	//3.激活线程1
	SetEvent(g_ThreadEvent[0]);
	//4.等待所有的线程完成赋值
	WaitForSingleObject(g_OK, INFINITE);
 
	//g_write[g_index] = '\0';
	cout << g_write.c_str() << endl;
 
	//销毁线程
	for (int i = 0; i < THREAD_NUM; i++)
	{
		CloseHandle(hdl[i]);
		CloseHandle(g_ThreadEvent[i]);
	}
	DeleteCriticalSection(&g_cs);
}
unsigned int __stdcall Fun(void *pPM)
{
	
	int num = (int)pPM;
	
 
	for (int i = 0; i < g_loop;i++)
	{
		WaitForSingleObject(g_ThreadEvent[num], INFINITE);
		EnterCriticalSection(&g_cs);
		//printf(" 线程%d正在输入字符%c\n", num + 1, num + 'A');
		g_write += num + 'A';
		
		
		/*if (num+1==THREAD_NUM)
		{
			printf("\n");
		}*/
		LeaveCriticalSection(&g_cs);
		SetEvent(g_ThreadEvent[(num + 1) % THREAD_NUM]);
		
	}
	if (num + 1 == THREAD_NUM)
	{
		SetEvent(g_OK);
	}
 
	return 0;
}