} void* writer(void* arg) { pthread_rwlock_wrlock(&rwlock); // 获取写锁 shared_data++; printf("Writer: Written shared_data = %d ", shared_data); pthread_rwlock_unlock(&rwlock); // 释放锁 return NULL; } int main() { pthread_t reader_threads[5], writer_threads[2]; int...
而在此时间内,不允许其它的线程访问该资源。我们可以通过互斥锁(mutex),条件变量(condition variable)和读写锁(reader-writer lock)来同步资源。 与互斥锁相关API 互斥量(mutex)从本质上来说是一把锁,在访问共享资源前对互斥量进行加锁,在访问完成后释放互斥量上的锁。对互斥量进行加锁后,任何其他试图再次对互斥...
a. 多个线程可以同时获得读锁(Reader-Writer lock in read mode),但是只有一个线程能够获得写锁(Reader-writer lock in write mode) b. 读写锁有三种状态 i. 一个或者多个线程获得读锁,其他线程无法获得写锁 ii. 一个线程获得写锁,其他线程无法获得读锁 iii. 没有线程获得此读写锁 c. 类型为pthread_rwloc...
int pthread_mutex_lock(pthread_mutex_t *mutex); int pthread_mutex_trylock(pthread_mutex_t *mutex); int pthread_mutex_unlock(pthread_mutex_t *mutex); 2.读写锁:Reader-Writer Locks a.多个线程可以同时获得读锁(Reader-Writer lock in read mode),但是只有一个线程能够获得写锁(Reader-writer lock i...
pthread_rwLock_rdlock(&m_lock); }voidReaderUnLock() { pthread_rwLock_unlock(&m_lock); }voidWriterLock() { pthread_rwLock_wrlock(&m_lock); }voidWriterUnLock() { pthread_rwLock_unlock(&m_lock); }private://禁止对读写锁进行拷贝ReadWriteLock(constReadWriteLock&src); ...
/* Read-write lock types. */ #if defined __USE_UNIX98 || defined __USE_XOPEN2K enum { PTHREAD_RWLOCK_PREFER_READER_NP, PTHREAD_RWLOCK_PREFER_WRITER_NP, // 妈蛋,没用,一样reader优先 PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
That is, when a read lock request is entered, the operation would not merely check to see if the lock was currently held, but would need to also determine what kind of lock was being held. If a reader, then the requesting thread would be allowed entry; if a writer, the requesting ...
int pthread_mutex_lock(pthread_mutex_t *mutex); int pthread_mutex_trylock(pthread_mutex_t *mutex); int pthread_mutex_unlock(pthread_mutex_t *mutex); 2.读写锁:Reader-Writer Locks a.多个线程可以同时获得读锁(Reader-Writer lock in read mode),但是只有一个线程能够获得写锁(Reader-writer lock ...
std::shared_lock<std::shared_mutex>lock(shared_mtx);std::cout<<"Reader "<<id<<" read value...
pthread_mutex_t rw_mutex;//basic lock on this structpthread_cond_t rw_condreaders;//for readerpthread_cond_t rw_condwriteres;//for writerintrw_magic;//for error checkingintrw_nwaiterreaders;//the num of readersintrw_nwaiterwirteres;//the num of writersintrw_refcount;//-1 is writer ...