操作系统：生产者消费者问题

#include <iostream>
#include <process.h>
#include <windows.h>

// 生产者消费者问题，单个生产者，多个消费者，多个缓冲池
// 使用 信号量  和 关键段 来实现

using namespace std;

int gi,gj;

const int num = 10;  // 产生数据的个数
const int size = 4;  // 缓冲池的大小
volatile bool flag = true;  // 用于消费者线程之间

int buf[size];  // 缓冲池

CRITICAL_SECTION gc; // 关键段

HANDLE empty,full; // Semaphore

unsigned int __stdcall pro(PVOID p)  // 生产者线程
{
for(int i = 0; i <= num ; i++)
{
WaitForSingleObject(empty,INFINITE);  // 线程同步

EnterCriticalSection(&gc);  // 线程互斥

buf[gi] = i;
cout << "生产者在 " << gi << " 号缓冲池放入 " << buf[gi] << endl;
gi = (gi+1)%size;

LeaveCriticalSection(&gc);

ReleaseSemaphore(full,1,NULL);

}

cout << "生产者运行结束!" << endl;

return 0;

}

unsigned int __stdcall cus(PVOID p)  // 消费者线程
{
while(true)
{

WaitForSingleObject(full,INFINITE);  // 线程同步
if( flag == false )  // 线程之间的逻辑判断
{
break;
}

EnterCriticalSection(&gc);  // 线程互斥

cout << "线程 " << GetCurrentThreadId() << " 在缓冲池 " << gj << " 获取数据 " << buf[gj] << endl;

if( buf[gj] == num )  // 结束条件
{
LeaveCriticalSection(&gc);
ReleaseSemaphore(full,1,NULL);
flag = false;
break;
}

gj = (gj+1)%size;
LeaveCriticalSection(&gc);

Sleep(50);

ReleaseSemaphore(empty,1,NULL);

}
cout << "消费者线程 " << GetCurrentThreadId() << " 运行结束!" << endl;
return 0;
}

int main()
{
// 相关变量的定义
const int sz = 3;
gi = gj = 0;
InitializeCriticalSection(&gc);
empty = CreateSemaphore(NULL,4,4,NULL);
full = CreateSemaphore(NULL,0,4,NULL);

HANDLE hand[sz];

hand[0] = (HANDLE)_beginthreadex(NULL,0,pro,NULL,0,NULL);  // 创建了三个线程
hand[1] = (HANDLE)_beginthreadex(NULL,0,cus,NULL,0,NULL);
hand[2] = (HANDLE)_beginthreadex(NULL,0,cus,NULL,0,NULL);

WaitForMultipleObjects(sz,hand,true,INFINITE);

//  资源的释放
CloseHandle(full);
CloseHandle(empty);

DeleteCriticalSection(&gc);

for(int i = 0; i < sz ; i++)
{
CloseHandle(hand[i]);
}

return 0;

}