VC 下臨界區變量（互斥鎖）

VC 下保證原子性的操作

這裏臨界區控制結構體操作都是基於這個結構體的

typedef struct CRITICAL_SECTION {
    unsigned int LockCount;         /* Nesting count on critical section */
    HANDLE OwnerThread;             /* Handle of owner thread */
    HANDLE hCrit;                    /* Handle to this critical section */
    DWORD needtrap;                    /* Trap in when freeing critical section */
    DWORD dwContentions;            /* Count of contentions */
} CRITICAL_SECTION, *LPCRITICAL_SECTION;

 

void InitializeCriticalSection(LPCRITICAL_SECTION lpCriticalSection )；//初始化

void WINAPI EnterCriticalSection(__inout LPCRITICAL_SECTION lpCriticalSection);//上鎖

void WINAPI LeaveCriticalSection( _Inout_LPCRITICAL_SECTION lpCriticalSection);//解鎖

void WINAPI DeleteCriticalSection(_Inout_ LPCRITICAL_SECTION lpCriticalSection);//釋放臨界區內存

上鎖以後就會讓其他線程在訪問到臨界區變量（全局變量）的時候進行等待 

直到解鎖以後才能使用。

#include <stdio.h>
#include <windows.h>

HANDLE hThread_1;
HANDLE hThread_2;
HANDLE hThread_3;
int n;
class StaticLock
{
public:
	StaticLock()
	{
		InitializeCriticalSection(&g_csTerm);
	};
	~StaticLock()
	{
		DeleteCriticalSection(&g_csTerm);
	};
	void lockon()
	{
		EnterCriticalSection(&g_csTerm);
	};
	void lockoff()
	{
		LeaveCriticalSection(&g_csTerm);
	};
private:
	CRITICAL_SECTION g_csTerm;
};
StaticLock lock;
DWORD WINAPI fun(LPVOID)
{
	while(1)
	{
		lock.lockon();
		if(n>50)
		{
			break;
		}	
		else 
		{
			++n;
			printf("%d\n",n);
		}
		lock.lockoff();
	}
	lock.lockoff();
}

int main(void) 
{
	
	n  = 0;
	hThread_1 = CreateThread(NULL,0,fun,NULL,0,NULL);
	hThread_1 = CreateThread(NULL,0,fun,NULL,0,NULL);
	hThread_1 = CreateThread(NULL,0,fun,NULL,0,NULL);
	
	WaitForSingleObject(hThread_1, INFINITE);
    WaitForSingleObject(hThread_2, INFINITE);
    WaitForSingleObject(hThread_3, INFINITE);
	
	
    CloseHandle(hThread_1);
    CloseHandle(hThread_2);
    CloseHandle(hThread_3);
	return 0;	
}