Synchronized block in C++

출처 : http://ricanet.com/new/view.php?id=blog/050807

ACriticalSection someCriticalSection;
synchronized(someCriticalSection)
{
    ...
}  

1. 생성과 해제를 통한 자원 획득, 해제

class AutoLock
{
public:
    AutoLock( ACriticalSection& cs ) : cs(cs)
    {
        cs.Lock();
        cont = true;
    }
    ~AutoLock()
    {
        cs.Unlock();
    }
private:
    ACriticalSection&  cs;
};
{
    AutoLock(someCriticalSection);
    ...
}

2. for문을 이용한 매크로

class AutoLock
{
public:
    AutoLock( ACriticalSection& cs ) : cs(cs)
    {
        cs.Lock();
        cont = true;
    }
    ~AutoLock()
    {
        cs.Unlock();
    }
    void P()
    {
        cont = false;
    }
    bool C()
    {
        return cont;
    }
private:
    ACriticalSection&  cs;
    bool cont;
};
#define synchronized(A)    for(AutoLock _syncVar(A); _syncVar.C(); _syncVar.P())

3. 2번 예제의 문제점 1 - break

for( ... )
{
    synchronized(someCriticalSection)
    {
        if( blahblah )
            break;
    }
    // here
}
// there

4. 2번 예제의 문제점2 - VC 6.0

//  May cause a problem in VC 6.0
synchronized(someCriticalSection)
{
    ...
}
synchronized(someCriticalSection)
{
    ...
}

5. if문을 이용한 매크로

class AutoLock
{
public:
    AutoLock( ACriticalSection& cs ) : cs(cs)
    {
        cs.Lock();
    }
    ~AutoLock()
    {
        cs.Unlock();
    }
    operator bool()
    {
        return true;
    }
private:
    ACriticalSection&  cs;
};
#define synchronized(A)        if( AutoLock _syncVar = A )