ISO/IEC 11404:2007

Overview

ISO/IEC 11404:2007 - Information technology: General-Purpose Datatypes (GPD) - defines a shared nomenclature and semantics for a set of datatypes commonly used across programming languages and software interfaces. The standard specifies both primitive datatypes (defined ab initio) and non‑primitive datatypes (defined in terms of other datatypes), and it formalizes three complementary notions of datatype: conceptual (abstract), structural, and implementation. ISO/IEC 11404:2007 enables consistent datatype descriptions, supports structural construction of new datatypes from GPDs, and prescribes the required information content for mappings between GPDs and language- or platform-specific datatypes.

Key topics and technical requirements

• Datatype taxonomy: Definitions of primitive and non-primitive datatypes commonly found in programming languages and interfaces.
• Three notions of datatype:
  • Abstract (conceptual) - value spaces and properties;
  • Structural - composition from component datatypes;
  • Implementation - representation rules in a given environment.
• Datatype properties: Equality, ordering, bounds, cardinality, numeric vs. non-numeric, exact/approximate.
• Aggregate datatypes: Records, classes, sets, bags, sequences, arrays, tables - with rules for homogeneity, size, uniqueness, ordering and access methods.
• Generated datatypes and generators: Choice, pointer, procedure, and other generators for building complex types.
• Specification language elements: Lexical conventions, identifiers, literals, annotations, declarations (type, value, termination), and normative datatype declaration forms.
• Mappings and conformance: The standard specifies required elements of a mapping between GPDs and another language’s datatypes (information content required), and defines conformance types (direct, indirect, mapping-standard conformance, and GPD program conformance).
• Extensibility: Mechanisms to define datatypes structurally in terms of the GPDs and to declare subtypes, ranges, and extensions.

Applications

• Creating language‑neutral API contracts and interface specifications for cross‑platform systems.
• Defining consistent datatype vocabularies for middleware, data interchange, and protocol design.
• Assisting compiler and tool vendors in mapping language-specific types to a common conceptual model.
• Supporting system integrators and architects who need precise datatype semantics for interoperability and validation.

Who should use it

• Standards bodies, API architects, language designers, compiler/tool implementers, middleware developers, and systems engineers focused on datatype interoperability, interface specification, and formal datatype mapping.

Related standards

• ISO/IEC 11404 complements other ISO/IEC standards addressing programming languages, data interchange, and interface description; use it as the canonical GPD vocabulary when documenting or mapping datatypes across technologies.