The meaning of a value stored in an object or returned by a function is determined by the type of the expression used to access it. (An identifier declared to be an object is the simplest such expression: the type is specified in the declaration of the identifier.) Types are partitioned into object types (types that describe objects), function types (types that describe functions), and incomplete types (types that describe objects but lack information needed to determine their sizes).
This section uses Eli's Operator Identification Language OIL to formalize the standard's description of types (Section 4.1.1), conversions among types (Section 4.1.2) and type constraints on operators (Section 4.1.3).