ISO/IEC 9899:2024

This document specifies the form and establishes the interpretation of programs written in the C programming language. It is designed to promote the portability of C programs among a variety of data-processing systems. It is intended for use by implementers and programmers. It specifies:
— the representation of C programs;
— the syntax and constraints of the C language;
— the semantic rules for interpreting C programs;
— the representation of input data to be processed by C programs;
— the representation of output data produced by C programs;
— the restrictions and limits imposed by a conforming implementation of C.
This document does not specify:
— the mechanism by which C programs are transformed for use by a data-processing system;
— the mechanism by which C programs are invoked for use by a data-processing system;
— the mechanism by which input data are transformed for use by a C program;
— the mechanism by which output data are transformed after being produced by a C program;
— the size or complexity of a program and its data that will exceed the capacity of any specific data-processing system or the capacity of a particular processor;
— all minimal requirements of a data-processing system that is capable of supporting a conforming implementation.
Annex J gives an overview of portability issues that a C program can encounter.