Chapter 14. Dynamic Entries

14.1. Introduction

As described in System V ABI, if an object file participates in dynamic linking, its program header table shall have an element of type PT_DYNAMIC. This `segment' contains the .dynamic section. A special symbol, _DYNAMIC, labels the section, which contains an array of the following structures.

typedef struct {
	Elf32_Sword	d_tag;
   	union {
   		Elf32_Word	d_val;
   		Elf32_Addr	d_ptr;
	} d_un;
} Elf32_Dyn;

extern Elf32_Dyn	_DYNAMIC[];

typedef struct {
	Elf64_Sxword	d_tag;
   	union {
   		Elf64_Xword	d_val;
   		Elf64_Addr	d_ptr;
	} d_un;
} Elf64_Dyn;

extern Elf64_Dyn	_DYNAMIC[];

Figure 14-1. Dynamic Structure

For each object with this type, d_tag controls the interpretation of d_un.