Is Short-Circuit Evaluation Guaranteed in C for User-Defined Types?

Short Circuit Evaluation in C : A Cautionary Tale

In Java, short-circuit evaluation ensures that the right operand of a logical operator is only executed if the left operand evaluates to true. This behavior enables efficient code execution by avoiding unnecessary computations.

Now, let's consider a similar scenario in C :

if (a != 0 && a->fun());

While this code emulates the desired behavior in Java, it's important to note that short-circuit evaluation for user-defined types is not guaranteed in C . This means that the a->fun() call could be executed even if a is null, leading to undefined behavior.

The reason behind this discrepancy lies in the overloaded nature of the logical operators && and || in C . When applied to user-defined types, these operators can be customized by the programmer, potentially overriding the default behavior of short-circuit evaluation.

Therefore, to ensure portability and avoid unpredictable results, it's strongly advised to refrain from overloading the && and || operators for custom types. For built-in types like int and bool, however, short-circuit evaluation is guaranteed, allowing you to utilize this powerful optimization technique in C as you would in Java.

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