When Should You Return by Const Reference in C ?

Const Returning Values in C

In C , the purpose of returning a value by const reference is to prevent unintentional modifications of the returned object. Consider the following code snippet:

const Object myFunc() {
    return myObject;
}

By declaring the return value as const, we ensure that the returned object cannot be modified accidentally. This is particularly useful in scenarios where a temporary object is returned and we do not want the caller to modify it inadvertently.

One potential drawback of returning by const value is that it can limit the caller's ability to perform certain operations on the returned object. For example, we cannot use arithmetic operators on the returned object directly without assigning it to a non-const variable.

In modern C practice, it is generally recommended to return values as non-const instead. This allows the caller to take advantage of rvalue references, which offer performance benefits by avoiding unnecessary copying.

While the reasons for returning by const value may have been valid in the past, advancements in the language and the widespread use of rvalue references make it obsolete in most cases.

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