for(int i = 0; i < 10000; i++) { shared_ptr<int> temp = global_instance; } // This is not thread-safe. While all the threads are the same, the // "final" value of this is almost certainly NOT going to be // number_of_threads*10000 = 100,000. It'll be something else....
#include<iostream>#include<memory>#include<thread>#include<chrono>#include<mutex>#include<vector>std::shared_ptr<int>global_instance=std::make_shared<int>(0);std::mutexm;constexprintmax_loop=10000;voidthread_fcn(){// thread-safe reference countingfor(inti=0;i<max_loop;i++){std::shared_...
std::this_thread::sleep_for(987ms); //线程睡眠987毫秒 std::shared_ptr<Base> lp = p; // thread-safe, even though the // shared use_count is incremented { static std::mutex io_mutex; std::lock_guard<std::mutex> lk(io_mutex); print("Local pointer in a thread:", lp); } } ...
std::shared_ptr<Base> lp = p; // thread-safe, even though the // shared use_count is incremented { static std::mutex io_mutex; std::lock_guard<std::mutex> lk(io_mutex); std::cout << "local pointer in a thread:\n" << " lp.get() = " << lp.get() << ", lp.use_cou...
一个最朴素的想法是,使用智能指针管理节点。事实上,如果平台支持std::atomic_is_lock_free(&some_shared_ptr)实现返回true,那么所有内存回收问题就都迎刃而解了(我在X86和Arm平台测试,均返回false)。示例代码(文件命名为lock_free_stack.h)如下: #pragmaonce#include#includetemplate<typenameT>classLockFreeStack{...
Note that the control block of ashared_ptris thread-safe: differentstd::shared_ptrobjects can be accessed using mutable operations, such asoperator=orreset, simultaneously by multiple threads, even when these instances are copies, and share the same control block internally. ...
shared_ptrcopy in every call. Notice that this doesn't copy theRuleMessageinstance, which could be costly, but copying astd::shared_ptris not cheaper than a reference because its control block is guaranteed to be thread-safe, and thus these copies use synchronization primitives (such as ...
{ std::this_thread::sleep_for(std::chrono::seconds(1)); std::shared_ptr<Base> lp = p; // thread-safe, even though the // shared use_count is incremented { static std::mutex io_mutex; std::lock_guard<std::mutex> lk(io_mutex); std::cout << "local pointer in a thread:\n...
not thread-safe the fake unique_ptr does not at all conform to the standard, and so is only a placeholder for use with older compilers ### Supported platforms: Developments and tests are done under the following OSs : Debian 7 (testing) ...
这里没有std::unique_ptr提供的一些东西，特别是别名构造函数(因此您可以拥有所引用的对象的包含对象)和...