Why is There No `std::is_struct` Type Trait in C ?

Why is There No std::is_struct Type Trait?

In C , it's common to use std::is_class to determine if a type is a class. However, you may wonder why there isn't a std::is_struct to distinguish between structs and classes.

The Misconception:

It's often assumed that structs and classes are distinct entities in C . However, this is a misconception.

The Truth:

Starting in 1985, C introduced a unified class model, eliminating the distinction between structs and classes. The struct keyword is merely a syntactic sugar that defines a class with default member visibility.

Why No Type Trait:

Since structs and classes are essentially the same type in C , there is no need for a separate std::is_struct type trait. std::is_class correctly identifies both structs and classes as classes.

Conclusion:

The absence of std::is_struct reflects the fact that C considers structs and classes as one and the same. The type trait std::is_class adequately captures the notion of class types without the need for a separate check for structs.

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