std_types.ch

max_align_t is a type whose alignment requirement is at least as strict (as large) as that of every scalar type.

nullptr_t is the type of the predefined null pointer constant, nullptr. It is a distinct type that is not itself a pointer type. It can be implicitly converted to any pointer type or bool, and the result is the null pointer value of that type or false respectively. No type other than nullptr_t itself can be converted or explicitly cast to nullptr_t.

a typedef for the same type as size_t, used to self-document functions that range-check their parameters at runtime

a typedef for the type int, used to self-document functions that return errno values