Linux条件变量pthread_condition细节(为何先加锁,pthread_cond_wait为何先解锁,返回时又加锁),程序员大本营,技术文章内容聚合第一站。
The waiting thread unblocks only after another thread calls pthread_cond_signal(3), or pthread_cond_broadcast(3) with the same condition variable, and the current thread reac- quires the lock on mutex. thread_cond_wait 的主要功能是: 释放互斥锁:线程在等待条件变量之前,必须释放与之关联的互斥...
int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex); DESCRIPTION Thepthread_cond_wait()function blocks on the specified condition variable, which atomically releases the specified mutex and causes the calling thread to block on the condition variable The blocked thread may be awak...
The mutex passed to pthread_cond_wait protects the condition.The caller passes it locked to the function, which then atomically places the calling thread on the list of threads waiting for the condition and unlocks the mutex. This closes the window between the time that the condition is checked...
pthread_cond_wait() 用于阻塞当前线程,等待别的线程使用pthread_cond_signal()或pthread_cond_broadcast来唤醒它。 pthread_cond_wait() 必须与pthread_mutex 配套使用。pthread_cond_wait()函数一进入wait状态就会自动release mutex。当其他线程通过pthread_cond_signal()或pthread_cond_broadcast,把该线程唤醒,使pthrea...
LINUX环境下多线程编程肯定会遇到需要条件变量的情况,此时必然要使用pthread_cond_wait()函数。但这个函数的执行过程比较难于理解。 pthread_cond_wait()的工作流程如下(以MAN中的EXAMPLE为例): Consider two shared variables x and y, protected by the mutex mut, and a condition vari- ...
boolbusy;condition_variablenonbusy;public:voidacquire(){if(busy==true){nonbusy.wait()}busy=true...
LINUX环境下多线程编程肯定会遇到需要条件变量的情况,此时必然要使用pthread_cond_wait()函数。但这个函数的执行过程比较难于理解。 pthread_cond_wait()的工作流程如下(以MAN中的EXAMPLE为例): Consider two shared variables x and y, protected by the mutex mut, and a condition vari- ...
pthread_cond_wait()的工作流程如下(以MAN中的EXAMPLE为例): Consider two shared variables x and y, protected by the mutex mut, and a condition vari- able cond that is to be signaled whenever x becomes greater than y. int x,y; pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER; ...
的竞争条件(Race Condition)。mutex互斥锁必须是普通锁(PTHREAD_MUTEX_TIMED_NP) 或者适应锁(PTHREAD_MUTEX_ADAPTIVE_NP),且在调用pthread_cond_wait()前必须由本线程加锁(pthread_mutex_lock()), 而在更新条件等待队列以前,mutex保持锁定状态,并在线程挂起进入等待前解锁。