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

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

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

You can either:

man readelf

or look at these tutorials:

• The ELF Object File Format by Dissection
• Understanding ELF using readelf and objdump.

I think Ndx field shows the section number where that symbol is defined.

Do a readelf -a <file>, and find out which section the address corresponds to for a given symbol.

I bet the section number of that section will appear in Ndx field.

Ok this question is old, but good old Google yields it if you are looking for readelf symboltable and NDX;

Here is what I found out:

The C code compiled with avr-gcc:

int XYZ = 123;
int ABC;

when the generated elf file is analyzed using

readelf --symbols KoreOS.elf

you get as output:

Num:    Value  Size Type    Bind   Vis      Ndx Name
...
148: 0080200b     2 OBJECT  GLOBAL DEFAULT    2 XYZ
...
258: 00803878     2 OBJECT  GLOBAL DEFAULT    3 ABC
...

I use the NDX column as hint if the variable is initialized or not. But I found no documentation anywhere so I'm just guessing.

greetings, Dominik