注意PTHREAD_MUTEX_INITIALIZER 是8个成员的结构体,与pthread_mutex_t定义相符。并且所有成为初始化为0。 初始化之后,我们接着看看pthread_mutex_lock操作: 1#ifndef __pthread_mutex_lock2strong_alias (__pthread_mutex_lock, pthread_mutex_lock)3hidden_def (__pthread_mutex_lock)4#endif56int7__pthread_mu...
pthread_mutex_unlock(pthread_mutex_t *mutex); DESCRIPTION If the current thread holds the lock on mutex, then the pthread_mutex_unlock() function unlocks mutex. Calling pthread_mutex_unlock() with a mutex that the calling thread does not hold will result in undefined behavior. RETURN VALUES I...
6. 步骤四:调用pthread_mutex_lock函数 最后,我们需要调用pthread_mutex_lock函数来实现互斥锁的加锁。下面是调用pthread_mutex_lock函数的代码: mutex=pthread_mutex_t()# 创建互斥锁对象# 调用pthread_mutex_lock函数result=pthread_mutex_lock(ctypes.byref(mutex))ifresult==0:print("互斥锁加锁成功")else:pri...
pthread_mutex_t *mutex; int pthread_mutex_unlock (mutex) pthread_mutex_t *mutex; 描述 通过调用pthread_mutex_lock来锁定mutex参数引用的互斥对象。 如果互斥对象已锁定,那么调用线程将阻塞,直到互斥对象变为可用为止。 此操作将返回由处于锁定状态的mutex参数引用的互斥对象,调用线程作为其所有者。
pthread_mutex_unlock(&(((ct_sum*)cnt)->lock)); pthread_exit(NULL);return0; }void* add2(void*cnt) {inti; cnt= (ct_sum*)cnt; pthread_mutex_lock(&(((ct_sum*)cnt)->lock)); printf("get lock thread2 id:%lu\n", pthread_self()); ...
futex全称是fast user-space locking,也就是快速用户空间锁,在linux下使用C语言写多线程程序时,在需要线程同步的地方会经常使用pthread_mutex_lock()函数对临界区进行加锁,如果加锁失败线程就会挂起,这就是互斥锁。但是pthread_mutex_lock并不是立即进行系统调用,而是首先在用户态进行CAS操作,判断其它线程是否已经获取...
If the mutex type is PTHREAD_MUTEX_RECURSIVE, then the mutex maintains the concept of a lock count. When a thread successfully acquires a mutex for the first time, the lock count is set to 1. Every time a thread relocks this mutex, the lock count is incremented by one. Each time the...
PTHREAD_MUTEX_RECURSIVE A recursive type mutex permits a thread to lock many times. That is, a thread attempting to relock this mutex without first unlocking will succeed. This type of mutex must be unlocked the same number to times it is locked before the mutex will be returned to an unlo...
pthread_mutex_lock函数是通过使用互斥锁来实现线程同步的。它的声明如下: int pthread_mutex_lock(pthread_mutex_t *mutex); 其中,参数mutex是一个指向互斥锁的指针。下面是使用pthread_mutex_lock的基本步骤: 1.定义互斥锁: pthread_mutex_t mutex; 2.初始化互斥锁: pthread_mutex_init(&mutex, NULL); 3.加...