implement auto lock and unlock via a simple using way

lock.cc

#include <cstdio>
#include <climits>
#include <cctype>
#include <cmath>
#include <cstring>

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>

using namespace std;

#define ARR_SIZE(x)     ((int)sizeof(x)/sizeof(x[0]))

#ifndef NDEBUG      /* fllow the macor `NDEBUG` from assert.h */
# define _D(...)    printf(__VA_ARGS__)
#else
# define _D(...)    ((void)0)
#endif

class Lock {
private:
    pthread_mutex_t *lock;

public:
    Lock(pthread_mutex_t &mutex) {
        lock = &mutex;
        pthread_mutex_lock(lock);
    }

    ~Lock() {
        pthread_mutex_unlock(lock);
    }
};

#define lock1(lk) if (Lock(lk), 1)

#define lock2(lk) \
    for (int __quit__ = 0; \
        !__quit__ && (pthread_mutex_lock(lk), 1); \
        __quit__ = 1, pthread_mutex_unlock(lk))

int main(int argc, char **argv)
{
    pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

    lock1(mutex) {
        printf("use lock with c++ style\n");
    }

    lock2(&mutex) {
        printf("use lock with c style\n");
    }

    return 0;
}