The term "thread-safe" refers to a property of code that ensures it functions correctly when accessed by multiple threads simultaneously. In a multi-threaded environment, thread-safe code prevents data races and ensures that shared data structures are manipulated in a manner that guarantees safe execution by multiple threads at the same time.
Key Points of Thread Safety:
Correctness Under Concurrency:
Thread-safe code behaves correctly when accessed from multiple threads, regardless of the scheduling or interleaving of those threads by the runtime environment[1][2][3][8].
Avoidance of Data Races:
Thread safety involves avoiding data races, which occur when multiple threads access and modify shared data concurrently without proper synchronization, leading to unpredictable results[4][6][7].
Synchronization Mechanisms:
Various strategies can be employed to achieve thread safety, including:
Synchronization: Using locks or other synchronization primitives to control access to shared resources[3][7][8].
Immutability: Making shared data immutable so that it cannot be modified after creation[3][8].
Thread Confinement: Ensuring that data is only accessible by a single thread[3][8].
Thread-safe Data Types: Using data structures that are inherently thread-safe[3][8].
Performance Considerations:
While thread safety is crucial for correctness, it often comes with a performance cost due to the overhead of synchronization mechanisms. Therefore, it is sometimes preferable to use non-thread-safe alternatives in single-threaded contexts for better performance[1][4].
Levels of Thread Safety:
There are different levels of thread safety, such as:
Serializable: Ensuring that code can be executed by multiple threads in a serialized manner using a single lock.
