Chapter 9. Symbol Versioning

9.1. Introduction

This chapter describes the Symbol Versioning mechanism. All ELF objects may provide or depend on versioned symbols. Symbol Versioning is implemented by 3 section types: SHT_GNU_versym, SHT_GNU_verdef, and SHT_GNU_verneed.

The prefix Elfxx in the following descriptions and code fragments stands for either "Elf32" or "Elf64", depending on the architecture.

Versions are described by strings. The structures that are used for symbol versions also contain a member that holds the ELF hashing values of the strings. This allows for more efficient processing.