String table sections hold null-terminated character sequences, commonly called strings. The object file uses these strings to represent symbol and section names. One references a string as an index into the string table section. The first byte, which is index zero, is defined to hold a null character. Likewise, a string table's last byte is defined to hold a null character, ensuring null termination for all strings. A string whose index is zero specifies either no name or a null name, depending on the context. An empty string table section is permitted; its section header's sh_size member would contain zero. Non-zero indexes are invalid for an empty string table.
A section header's sh_name member holds an index into the
section header string table section, as designated by the
e_shstrndx member of the ELF header. The following tables
show a string table with 25 bytes and the strings associated with various
indexes.
| Index | +0 | +1 | +2 | +3 | +4 | +5 | +6 | +7 | +8 | +9 |
|---|---|---|---|---|---|---|---|---|---|---|
| 0 | \0 | n | a | m | e | . | \0 | V | a | r |
| 10 | i | a | b | l | e | \0 | a | b | l | e |
| 20 | \0 | \0 | x | x | \0 | |||||
String Indexes
| Index | String |
|---|---|
| 0 | none |
| 1 | name. |
| 7 | Variable |
| 11 | able |
| 16 | able |
| 24 | null string |
As the example shows, a string table index may refer to any byte in the section. A string may appear more than once; references to substrings may exist; and a single string may be referenced multiple times. Unreferenced strings also are allowed.