What is the meaning of the term “thread-safe”?

Question

Does it mean that two threads can\'t change the underlying data simultaneously? Or does it mean that the given code segment will run with predictable results when multiple t

Answer 1

Don't confuse thread safety with determinism. Thread-safe code can also be non-deterministic. Given the difficulty of debugging problems with threaded code, this is probably the normal case. :-)

Thread safety simply ensures that when a thread is modifying or reading shared data, no other thread can access it in a way that changes the data. If your code depends on a certain order for execution for correctness, then you need other synchronization mechanisms beyond those required for thread safety to ensure this.