for(auto it:should)
时间: 2024-06-03 17:08:44 浏览: 125
This is a range-based for loop in C++, which iterates over each element in the container "should". The "auto" keyword allows the compiler to automatically determine the data type of each element in the container, based on the container type. The loop variable "it" is assigned to each element in turn, and the loop body executes once for each element in the container.
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void getAvailableListeners( std::vector<std::weak_ptr<T>> &availableListeners) { // Entering critical section, copy lockable shared_ptr from global listener std::lock_guardstd::mutex lock(listenerMutex_); for(auto it = listeners_.begin(); it != listeners_.end();) { auto sp = (*it).lock(); if(sp) { availableListeners.emplace_back(sp); ++it; } else { // if we unable to lock the listener, we should remove it from // listenerList LOG(DEBUG, "erased obsolete weak pointer from listeners"); it = listeners_.erase(it); } } } std::vector<std::weak_ptr<IRwsCatListener>> applisteners; if (listenerMgr_) { listenerMgr_->getAvailableListeners(applisteners); for (auto &wp : applisteners) { if (auto sp = wp.lock()) { LOG(DEBUG, "CardManager: invoking onECallEvent"); sp->onBipEvent(phoneId, bip_status); } } } else { LOG(ERROR, __FUNCTION__, " listenerMgr is null"); } 解释下这两段代码的意思和作用
这两段代码实现了一个调用监听器回调函数的过程。
首先,在第一段代码中,函数 getAvailableListeners 从 listeners_ 容器中获取所有可用的监听器,并将它们存储到 availableListeners 容器中。注意,这里使用了互斥锁来保护 listeners_ 容器,以防止多线程访问时发生数据竞争。
接下来,在第二段代码中,首先声明了一个 std::vector<std::weak_ptr<IRwsCatListener>> 类型的 applisteners 容器,用于存储从 listenerMgr_ 中获取到的所有监听器。然后,通过调用 listenerMgr_->getAvailableListeners(applisteners) 函数,从 listenerMgr_ 中获取所有可用的监听器,并存储到 applisteners 容器中。
接着,使用 for 循环遍历 applisteners 容器中的所有监听器,对于每个监听器,首先尝试将其转化为 shared_ptr,如果转化成功,则调用该监听器的 onBipEvent 函数,并传递 phoneId 和 bip_status 两个参数。如果转化失败,则说明该监听器已经被销毁,需要将其从 applisteners 容器中移除。
最后,如果 listenerMgr_ 为空,则记录一条错误日志。
C++ auto
C++ `auto` is a keyword introduced in C++11 that allows the compiler to automatically deduce the data type of a variable from its initializer. It can be used for any variable declaration, including function return types and lambda expressions.
For example, instead of explicitly specifying the data type of a variable:
```
int i = 10;
```
You can use `auto` to have the compiler deduce the data type:
```
auto i = 10;
```
`auto` is particularly useful when the type name is long or complex, or when working with templates where the exact data type may not be known until runtime. However, it should be used with caution to avoid ambiguity or unintended consequences.