ISO/IEC 23360-4-2:2021

Overview

ISO/IEC 23360-4-2:2021 - Linux Standard Base (LSB) - Part 4-2: Core specification for AMD64 (X86-64) architecture defines the architecture‑specific portion of the LSB Core module for the AMD64 / x86-64 platform. Intended to be used with the LSB Core - Generic document, this ISO standard specifies the Application Binary Interface (ABI) and supplements the common, architecture‑independent APIs so that compiled applications can run uniformly across LSB-conformant x86‑64 systems. The 2021 edition, prepared by the Linux Foundation, replaces the earlier 2006 edition and is primarily a binary interface definition addressing runtime behavior, libraries, and installation considerations.

Key topics and technical requirements

• ABI vs API: Focuses on the binary interface (ABIs) that must be implemented by distributions; source‑level APIs are referenced but the ABI is authoritative for compatibility.
• Executable and Linking Format (ELF): Defines ELF headers, sections, symbol tables, relocations, program headers, program loading and dynamic linking for x86‑64 binaries.
• Machine and calling conventions: Specifies low‑level machine interface, function calling sequence, process initialization and C stack frame details relevant to x86‑64.
• Base and utility libraries: Mandates interfaces and data definitions for core libraries such as libc, libm, libpthread, libdl, libcrypt, libgcc_s, and utilities like libz, libncurses and libstdc++ where applicable.
• Dynamic linker and symbol versioning: Requires a program interpreter/dynamic linker behavior consistent with the LSB to enable backward compatibility across LSB versions.
• Package format & installation: Provides guidelines for a minimal install environment and package architecture considerations so installation scripts and high‑volume applications behave predictably.
• Conformance rules: Implementation and application conformance requirements are defined; interfaces in this part are mandatory unless explicitly stated otherwise.

Practical applications

• Ensure binary portability of commercial and high‑volume applications across x86‑64 Linux distributions.
• Guide OS vendors and distribution maintainers in implementing a compatible runtime environment (dynamic linker, core libraries).
• Help software packagers and ISVs certify binaries for LSB compatibility and reduce fragmentation across Linux platforms.
• Inform compiler writers, toolchain maintainers, and system integrators about calling conventions, ELF usage, and ABI constraints.

Who should use this standard

• Linux distribution engineers and maintainers
• Application developers and software vendors targeting binary distribution on x86‑64 Linux
• Compiler and toolchain developers
• QA and certification teams validating LSB conformance

Related standards

• LSB Core - Generic (architecture‑independent part) - required to be used in conjunction with this part
• Other parts of the ISO/IEC 23360 series covering additional architectures and modules

Keywords: Linux Standard Base, LSB, ISO/IEC 23360-4-2:2021, AMD64, x86-64, ABI, API, ELF, dynamic linking, libc, package installation, conformance.