Version Definition Section

This section is defined by the type SHT_SUNW_verdef. If this section exists, a SHT_SUNW_versym section must also exist. Using these two structures, an association of symbols-to-version definitions is maintained within the file (see "Creating a Version Definition" for more details). Elements of this section have the following structure:

typedef struct {
        Elf32_Half      vd_version;
        Elf32_Half      vd_flags;
        Elf32_Half      vd_ndx;
        Elf32_Half      vd_cnt;
        Elf32_Word      vd_hash;
        Elf32_Word      vd_aux;
        Elf32_Word      vd_next;
} Elf32_Verdef;
 
typedef struct {
        Elf32_Word      vda_name;
        Elf32_Word      vda_next;
} Elf32_Verdaux;

typedef struct {
        Elf64_Half      vd_version;
        Elf64_Half      vd_flags;
        Elf64_Half      vd_ndx;
        Elf64_Half      vd_cnt;
        Elf64_Word      vd_hash;
        Elf64_Word      vd_aux;
        Elf64_Word      vd_next;
} Elf64_Verdef;
 
typedef struct {
        Elf64_Word      vda_name;
        Elf64_Word      vda_next;
} Elf64_Verdaux;

vd_version

This member identifies the version of the structure itself.

The value 1 signifies the original section format; extensions will create new versions with higher numbers. The value of VER_DEF_CURRENT changes as necessary to reflect the current version number.

vd_flags

This member holds version definition-specific information.

The base version definition is always present when version definitions, or symbol auto-reduction, has been applied to the file. The base version provides a default version for the files reserved symbols (see "Generating the Output Image"). A weak version definition has no symbols associated with it (see "Creating a Weak Version Definition" for more details).

vd_ndx

This member holds the version index. Each version definition has a unique index that is used to associate SHT_SUNW_versym entries to the appropriate version definition.

vd_cnt

This member indicates the number of elements in the Elf32_Verdaux array.

vd_hash

This member holds the hash value of the version definition name (this value is generated using the same hashing function described in "Hash Table").

vd_aux

This member holds the byte offset, from the start of this Elf32_Verdef entry, to the Elf32_Verdaux array of version definition names. The first element of the array must exist and points to the version definition string this structure defines. Additional elements can be present, the number being indicated by the vd_cnt value. These elements represent the dependencies of this version definition. Each of these dependencies will have its own version definition structure.

vd_next

This member holds the byte offset, from the start of this Elf32_Verdef structure, to the next Elf32_Verdef entry.

vda_name

This member holds a string table offset to a null-terminated string, giving the name of the version definition.

vda_next

This member holds the byte offset, from the start of this Elf32_Verdaux entry, to the next Elf32_Verdaux entry.