Does const Mean Thread-Safe in C 11?

Introduction

The notion of "thread-safety" in C 11 has been a subject of discussion surrounding the concept of "const." This article explores the relationship between const and thread-safety, clarifying misconceptions and providing a deeper understanding of the language's behavior.

Thread-Safety and const

The term "thread-safe" implies that an object can be accessed concurrently by multiple threads without causing data corruption. The C 11 standard defines thread-safety based on the absence of data races, which occur when two conflicting actions access or modify the same memory location.

In C 11, const objects are expected to be thread-safe operations performed on them are presumed to be read-only. This expectation arises from the Standard Library's requirement that standard library functions avoid data races on const objects.

const vs. Java's "Synchronized"

It is important to note that const in C 11 is not equivalent to Java's "synchronized." While Java's "synchronized" keyword explicitly enforces thread-safety, const in C 11 merely indicates that an object is not writable.

Thread-safety in C 11 is achieved through synchronization mechanisms such as locks and atomic operations. Const alone does not guarantee thread-safety; it only imposes a contract that operations on const objects are expected to be read-only.

Implications for Object Design

The distinction between thread-safety and const has implications for object design. If an object's data members are immutably set during construction, declaring the object as const ensures that concurrent access is thread-safe. However, if an object's state can be modified, additional synchronization mechanisms are necessary to make it truly thread-safe.

Conclusion

Const in C 11 implies an expectation of thread-safety, particularly in the context of the Standard Library. It is not a guaranteed thread-safety mechanism, as it does not enforce read-only access. De