# Symbol table (ivss)

A **symbol table** records names, bindings, sections, and values used during linking. For the reference example in [[ivss-object-files|Object files]], the assembler's dump includes these entries:

```text
Num  Value   Size Type  Bind Ndx Name
  3: 00000000   0 NOTYP GLOB UND target
  5: 00000000   0 NOTYP  LOC   3 slot
```

`target` is global but undefined: its zero value does not mean its address is zero. The linker must find a definition. `slot` is local and belongs to section three, `my_data`, at byte offset zero.

Each entry is stored as an `Elf_Sym`. Its `st_name` field is a byte offset into the [[ivss-string-table|string table]], while `st_shndx` identifies a section or a special value such as `SHN_UNDEF` or `SHN_ABS`. `st_info` packs binding and type.

A section-defined symbol's value becomes meaningful together with its section placement. An absolute symbol, such as one created by `.equ`, does not need a section base added. Relocations refer to symbol-table entry numbers, so preserving those relationships matters when objects are combined.

Source: [elf.h](https://github.com/yanevskiv/ivss/blob/main/h/elf.h), [elf.c](https://github.com/yanevskiv/ivss/blob/main/src/elf.c).