add2.c:

```
int counter=0;
int a=0;
int b;
int c;
int add(int a, int b) {
    return a+b;
}

```

compilation:
gcc -c add2.c -o add2.o

reading the symbol table:
readelf --symbols add2.o

```
Symbol table '.symtab' contains 12 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 00000000     0 FILE    LOCAL  DEFAULT  ABS add2.c
     2: 00000000     0 SECTION LOCAL  DEFAULT    1 
     3: 00000000     0 SECTION LOCAL  DEFAULT    2 
     4: 00000000     0 SECTION LOCAL  DEFAULT    3 
     5: 00000000     0 SECTION LOCAL  DEFAULT    5 
     6: 00000000     0 SECTION LOCAL  DEFAULT    4 
     7: 00000000     4 OBJECT  GLOBAL DEFAULT    3 counter
     8: 00000004     4 OBJECT  GLOBAL DEFAULT    3 a
     9: 00000004     4 OBJECT  GLOBAL DEFAULT  COM b
    10: 00000004     4 OBJECT  GLOBAL DEFAULT  COM c
    11: 00000000    14 FUNC    GLOBAL DEFAULT    1 add

```

What does "COM" means in the Ndx column ? I understand that "counter" and "a" are defined in the section #3 (ie, .bss) and that "add" is defined in the section #1 (ie, .text), but i was expecting "b" and "c" to be defined in the .bss section too, and so get a "3" in the Ndx column.

Thank you