ELF Object File Format

Foreword

The SVR4 ABI

The System V Release 4 (SVR4) Application Binary Interface (ABI) is composed of several components, ranging from a high-level specification of the programming interface to the low-level machine details. The ABI contains the following chapters:

  • Chapter 1: Introduction.

  • Chapter 2: Software Installation covers installation media, and physical distribution formats.

  • Chapter 3: Low Level System Information. This processor-dependent chapter covers the machine details, data representation, calling conventions, parameter passing, register usage, stack frame layout, stack unwinding, and dynamic linking conventions.

  • Chapter 4: Object Files covers the ELF object file format and relocatable objects.

  • Chapter 5: Program Loading and Dynamic Linking covers the ELF object file format, and executable and shared objects.

  • Chapter 6: Libraries covers the processor-independent API available to the program, and the processor-specific binding of the API to the binary interface. It provides structure layouts, values for symbolic contants, and other implementation-specific details left unspecified by the API document.

  • Chapter 7: Development Environment covers the development and packaging tools.

  • Chapter 8: Execution Environment covers the runtime environment, file system structure, and system services available to the running application.

The SVR4 ABI is published in two parts: a generic ABI document (gABI), which covers the machine-independent components of the ABI, and a processor-specific ABI supplement (psABI), published separately for each machine architecture supported by the SVR4 ABI.

The SVR4 gABI and several other ABIs share ELF as a common object file format, and the official specification of the ELF object file format is published here. This specification replaces the material that was contained in Chapters 4 and 5 of the SVR4 gABI document.