No, it means that the initialization of local statics is thread-safe. You definitely want to leave this feature enabled. Thread-safe initialization of local statics is very important. If you need generally thread-safe access to local statics then you will need to add the appropriate guards yourself.
Just call it from the main thread like this. Objective-C dispatch_async(dispatch_get_main_queue(), ^{ [[UIApplication delegate] fooBar]; }); Swift DispatchQueue.main.async { YourUIControlMethod() } Reaching out to your app delegate like this, is a hint that your architecture could use a little cleanup. You can call delegates from any thread you want. You only need to make sure … Read more
No, this code is absolutely, demonstrably not threadsafe. import threading i = 0 def test(): global i for x in range(100000): i += 1 threads = [threading.Thread(target=test) for t in range(10)] for t in threads: t.start() for t in threads: t.join() assert i == 1000000, i fails consistently. i += 1 resolves to four opcodes: … Read more
No, your code won’t lock access to the members of the object returned from MyProperty. It only locks MyProperty itself. Your example usage is really two operations rolled into one, roughly equivalent to this: // object is locked and then immediately released in the MyProperty getter MyObject o = MyProperty; // this assignment isn’t covered … Read more
You need to implement your own locking for all shared variables that will be modified in Python. You don’t have to worry about reading from the variables that won’t be modified (ie, concurrent reads are ok), so immutable types (frozenset, tuple, str) are probably safe, but it wouldn’t hurt. For things you’re going to be … Read more
Yes, it is: DateTimeFormat is thread-safe and immutable, and the formatters it returns are as well. and so is the Java 8 version Implementation Requirements: This class is immutable and thread-safe.
No, it isn’t. The instance is stateful. So you need to store it threadlocal, or to obtain a new instance on every encrypt/decrypt call, or to wrap it in a synchronized(cipher) block. Threadsafety is usually mentioned in javadocs as “is thread safe” or “is not thread safe”. This is not the case for Cipher, so … Read more
std::atomic bool type not guranteed to be lock-free? Correct. std::atomic may be implemented using locks. then it’s not atomic or what? std::atomic is atomic whether it has been implemented using locks, or without. std::atomic_flag is guaranteed to be implemented without using locks. So what’s the difference b/w two The primary difference besides the lock-free guarantee … Read more
It’s not thread safe. Simply create a new instance of DbContext in you thread.
If you want to guarantee that the other thread will read the latest value, you must use Thread.VolatileRead(). (*) The read operation itself is atomic so that will not cause any problems but without volatile read you may get old value from the cache or compiler may optimize your code and eliminate the read operation … Read more