What are the meanings of the columns of the symbol table displayed by readelf?

Swaroop S picture Swaroop S · Jun 17, 2010 · Viewed 35.2k times · Source

Could someone explain the columns shown of the symbol table using readelf?

Answer

Caladain picture Caladain · Jun 17, 2010

Consider the following:

Symbol table .symtab contains 1203 entries:

 Num:    Value  Size Type    Bind   Vis      Ndx Name
 310: a0008120     0 NOTYPE  GLOBAL DEFAULT  ABS _gp  
 734: a0000010    32 OBJECT  GLOBAL DEFAULT   77 v 
 818: 9d000018   496 FUNC    GLOBAL DEFAULT   71 main 
 849: a0000124     4 OBJECT  GLOBAL DEFAULT   78 phrase 
 955: a0000000     9 OBJECT  GLOBAL DEFAULT   77 peppers  
1020: a000023c   192 OBJECT  GLOBAL DEFAULT   80 bins
  • Num: = The symbol number
  • Value = The address of the Symbol
  • Size = The size of the symbol
  • Type = symbol type: Func = Function, Object, File (source file name), Section = memory section, Notype = untyped absolute symbol or undefined
  • Bind = GLOBAL binding means the symbol is visible outside the file. LOCAL binding is visible only in the file. WEAK is like global, the symbol can be overridden.
  • Vis = Symbols can be default, protected, hidden or internal.
  • Ndx = The section number the symbol is in. ABS means absolute: not adjusted to any section address's relocation
  • Name = symbol name