thread-safety

来源： https://stackoverflow.com/questions/63469182/are-parallelstreams-on-onetomany-collections-safe

问题 I have the following code where I'm trying to make a request to a remote endpoint using HttpClient : using (var client = new HttpClient()) { client.BaseAddress = _serviceBaseAddress; Task<HttpResponseMessage> readResponseTask = client.GetAsync(relativeUri); readResponseTask.Wait(); using (var response = readResponseTask.Result) { if (response.StatusCode == HttpStatusCode.NotFound || !response.IsSuccessStatusCode) { return default(TResult); } Task<TResult> readContentTask = response.Content

问题 imagine I write a library in C. Further, imagine this library to be used from a multi-threaded environment. How do I make it thread-safe? More specific: How do I assure, that certain functions are executed only by one thread at a time? In opposite to Java or C# for example, C has no means to deal with threads/locks/etc., nor does the C standard library. I know, that operating systems support threads, but using their api would restrict the compatibility of my library very much. Which

问题 I'm new to using Blocking Collection and threading and want to make sure I'm following best practice. I'm using a third party API that is not thread safe. I will be making multiple simultaneous requests to the API, so I need to add these requests to a queue and process them one after another. To do this I have a blocking collection: BlockingCollection<myEventArgs> myTasks = new BlockingCollection<myEventArgs>(); private void myEventHandler(object sender, myEventArgs e) { myTasks.Add(e); }

问题 I'm trying to develop a software with PyQt, but I often get stuck on software crashes without debug information (only the exit code 0xC0000409). I'm using QThread, and I wrote a system like this: class serialThreadC(QThread): updateOutBox = QtCore.pyqtSignal(str) updateStatus = QtCore.pyqtSignal(int) def __init__(self): super(serialThreadC, self).__init__() self.ser = False self.state = 0 self.serialEnabled = False def run(self): while True: if self.state == -3 or self.state == -2: if self

问题 This question already has answers here : C++ return value created before or after auto var destruction? (2 answers) in C++ which happens first, the copy of a return object or local object's destructors? [duplicate] (4 answers) Closed 2 years ago . Is the get_a() function safe for race-conditions or do I need to explicitly copy str_ as in get_b() in order to have a thread-safe function? class Class { public: auto get_a() -> std::string { auto&& guard = std::lock_guard{mutex_}; return str_; }

问题 I'm trying to create a multithreaded opengl application with libx11 - with one separate thread per window, and one manager thread. I have an event loop in the manager thread: while(true) while(XQLength(mPlatformData->display)){ XNextEvent(mPlatformData->display, &event); std::cout << "event" << std::endl; } } This is a great event loop for single threaded applications, but with this multithreaded setup strange things happen. When I'm creating a window, I need to disable the event queue, or

问题 I need to update a value in a ConcurrentHashmap but I am not sure on how to do this thread safe. The Hashmap is a ConcurrentHashMap and I need to get the instance of the custom class, perform some operations on it and then put the updated value back in. Is there any way to combine this get-alter-put operation to something atomic? Thanks in advance 回答1: You can use ConcurrentHashMaps computeIfPresent https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentHashMap.html

问题 I have a structure that needs to be generic over a type, yet the type is not actually contained in the structure: it's used in methods of this structure, not in the structure itself. And so, the structure includes a PhantomData member: pub struct Map<T> { filename: String, phantom: PhantomData<*const T>, } The phantom member is defined as a pointer because the structure does not actually own data of type T . This is per advice in the documentation of std::marker::PhantomData: Adding a field

问题 The last couple of days I've been reading about async/await. Yesterday I found this video on Channel 9 what made wonder about some things. Please consider the slide below. Aside from the issues Lucian Wischik addresses, I wondered about variable assignment. Say we changed the async void into async Task , and added await before the SendData call. This enables us to get the stream, assign the variable m_GetResponse , wait for two seconds and print it. But what happens to the variable? It could