Re: How does versioning work (was: Bug mixing old sem_wait and new pthread_cond_broadcast)

[John Reiser]

> |>   Why are two versions of libc.so.6 listed under libglib-1.2.so.0.0.9?
> 
> There are two _version symbols_ listed, both belonging to the same
> library.
> 
> |>   How does the system determine which versions are required for a given
> |> library?
> 
> It's encoded in the object image.  Use `objdump -p' to get a listing.

For more detailed, symbol-by-symbol information, use
        readelf --syms --version-info  module
where readelf is part of the gnu binutils package.

For example, on the /bin/date that I have, the --syms part includes

    26: 080489bc    58 FUNC    GLOBAL DEFAULT  UND address@hidden (2)
    27: 08048b0c   229 FUNC    GLOBAL DEFAULT  UND address@hidden (3)

and the --version-info part includes [note hex<->decimal conflict in labels]

  018:   2 (GLIBC_2.0)     2 (GLIBC_2.0)     2 (GLIBC_2.0)     3 (GLIBC_2.1)  
 
Version needs section '.gnu.version_r' contains 1 entries:
 Addr: 0x00000000080487c4  Offset: 0x0007c4  Link to section: 5 (.dynstr)
  000000: Version: 1  File: libc.so.6  Cnt: 2
  0x0010: Name: GLIBC_2.1  Flags: none  Version: 3
  0x0020: Name: GLIBC_2.0  Flags: none  Version: 2

-- 
John Reiser, address@hidden