What does the first column of numbers mean in objdump output?

Question

I used objdump -d a.out to get the following. I initially assumed that the first column (e.g. 080482b4) is the byte offset, but then I noticed that the file is only 7190 bytes long!

a.out:     file format elf32-i386


Disassembly of section .init:

080482b4 <_init>:
 80482b4:   53                      push   %ebx
 80482b5:   83 ec 08                sub    $0x8,%esp
 80482b8:   e8 00 00 00 00          call   80482bd <_init+0x9>
 80482bd:   5b                      pop    %ebx
 80482be:   81 c3 37 1d 00 00       add    $0x1d37,%ebx
 80482c4:   8b 83 fc ff ff ff       mov    -0x4(%ebx),%eax
 80482ca:   85 c0                   test   %eax,%eax
 80482cc:   74 05                   je     80482d3 <_init+0x1f>
 80482ce:   e8 3d 00 00 00          call   8048310 <__gmon_start__@plt>
 80482d3:   e8 e8 00 00 00          call   80483c0 <frame_dummy>
 80482d8:   e8 b3 01 00 00          call   8048490 <__do_global_ctors_aux>
 80482dd:   83 c4 08                add    $0x8,%esp
 80482e0:   5b                      pop    %ebx
 80482e1:   c3                      ret

score 4 · Accepted Answer · edited May 23 '17 at 11:54

4

It shows the virtual address where the code will be in the running image.

(By convention, code in Linux x86 ELF binaries typically starts at 0x08048000.)

edited May 23 '17 at 11:54

Community

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answered Nov 12 '11 at 17:18

Matthew Slattery

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Ohk. Thanks. Is there anyway to know the file offset? – AppleGrew Nov 12 '11 at 17:21
Yes: `objdump -h` will show the virtual memory address (VMA) and file offset of each section. – Matthew Slattery Nov 12 '11 at 17:26

What does the first column of numbers mean in objdump output?

1 Answers1