win32多线程编程与锁

模拟售票程序。

 

未加锁程序：

 

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

int index = 0;
int ti = 100;

DWORD WINAPI fun1(
				  LPVOID lpParameter
				  );
DWORD WINAPI fun2(
				  LPVOID lpParameter
				  );
void main()
{
	HANDLE hthread1;
	hthread1 = CreateThread(NULL,0,fun1,NULL,0,NULL);
	CloseHandle(hthread1);
	HANDLE hthread2;
	hthread2 = CreateThread(NULL,0,fun2,NULL,0,NULL);
	CloseHandle(hthread2);

	Sleep(4000);//这样主线程不占用CPU
	
}

DWORD WINAPI fun1(
				  LPVOID lpParameter
				  )
{
	while(true)
	{
		
		if (ti>0)
		{
			
			ti--;
			cout<<"thread 11111:"<<ti<<endl;
			
		}
		else
			break;
	
		
	}
		
	return 0;
}
DWORD WINAPI fun2(
				  LPVOID lpParameter
				  )
{
	while(true)
	{
	
		if (ti>0)
		{
			
			ti--;
			cout<<"thread 22222:"<<ti<<endl;
			Sleep(5);
			
		}
		else
			break;
	
		
	}
	return 0;
}

 

加锁程序：

 

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

int index = 0;
int ti = 100;
HANDLE hmutex;//锁
DWORD WINAPI fun1(
				  LPVOID lpParameter
				  );
DWORD WINAPI fun2(
				  LPVOID lpParameter
				  );
void main()
{
	HANDLE hthread1;
	hthread1 = CreateThread(NULL,0,fun1,NULL,0,NULL);
	CloseHandle(hthread1);
	HANDLE hthread2;
	hthread2 = CreateThread(NULL,0,fun2,NULL,0,NULL);
	CloseHandle(hthread2);
	hmutex = CreateMutex(NULL,TRUE,NULL);
//	WaitForSingleObject(hmutex,INFINITE);
	ReleaseMutex(hmutex);
	Sleep(4000);//这样主线程不占用CPU
	
}

DWORD WINAPI fun1(
				  LPVOID lpParameter
				  )
{
	while(true)
	{
		WaitForSingleObject(hmutex,INFINITE);
		if (ti>0)
		{
			
			ti--;
			cout<<"thread 11111:"<<ti<<endl;
			
		}
		else
			break;
		ReleaseMutex(hmutex);
		
	}
		
	return 0;
}
DWORD WINAPI fun2(
				  LPVOID lpParameter
				  )
{
	while(true)
	{
		WaitForSingleObject(hmutex,INFINITE);
		if (ti>0)
		{
			
			ti--;
			cout<<"thread 22222:"<<ti<<endl;
			Sleep(5);
			
		}
		else
			break;
		ReleaseMutex(hmutex);
		
	}
	return 0;
}

 

可以根据运行结果比较区别，未加锁程序显然存在BUG，多次售同一张票。