String Table

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 figures 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  

Figure 4-15: String Table 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.

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