코드 : rw-lock.c
#include 
#include 
#include 
#include "common_threads.h"
void *reader(void *arg);
void *writer(void *arg);
typedef struct _rwlock_t {
    sem_t writelock;
    sem_t mutex;
    int AR;       // number of Active Readers
} rwlock_t;
void rwlock_init(rwlock_t *rw) {
    rw->AR = 0;
    Sem_init(&rw->mutex, 1); 
    Sem_init(&rw->writelock, 1); 
}