Is "void" a scalar type?

From the C18 standard (6.2.5 §21) :

Arithmetic types and pointer types are collectively called scalar types.

void is neither an arithmetic type, nor a pointer type, so it's not a scalar type.

From 6.2.5 §19 :

The void type comprises an empty set of values; it is an incomplete object type that cannot be completed.

The type void is not considered a scalar type. It is actually an incomplete type.

Section 6.2.5 of the C standard regarding "Types" states the following regarding void in paragraph 19:

The void type comprises an empty set of values; it is an incomplete object type that cannot be completed.

And paragraph 21 defines scalar types as:

Arithmetic types and pointer types are collectively called scalar types. Array and structure types are collectively called aggregate types.

It is a special type category of its own. It is not a scalar type, but an incomplete type that you cannot declare an instance of.

From C17 6.2.5:

§18

Integer and floating types are collectively called arithmetic types.

§19

The void type comprises an empty set of values; it is an incomplete object type that cannot be completed.

§21

Arithmetic types and pointer types are collectively called scalar types.