Docs for --unresolved-symbols unclear?

[Vladimir Prus <ghost at cs dot msu dot su>]

Hi,
the docs for --unresolved-symbols option of ld, say:

   `ignore-all'
          Do not report any unresolved symbols.  This is the default
          when creating shared libraries or dynamic executables.

Unless I misunderstand what 'dynamic executables' means, this is not correct. 
On my system (Debian unstable), all binaries are dynamic by default. Say I 
compile file a.cpp with the following content:

    void foo();

    int main()
   {
        foo();
   }

With 

     g++ a.cpp

I get "unresolved symbol" error, as expected. But if I compile it with 

      g++ a.cpp -Wl,--unresolved-symbols=ignore-all

I get only warning, and binary crashes at runtime. So, it seems that default 
value of --unresolved-symbls is not "ignore-all".

Is it so, and what's the real default value, or I'm missing something?

TIA,
Volodya