Re: [Mingw-users] libstdc++ dependencies [SOLVED]

[JonY <jo...@us...>]

On 3/11/2013 21:11, Edward Rosten wrote:
> 
> I've not heard of that.
> 
> If you link to a .so, it tries to find all the symbols at link time
> and fails with a link error if you do not.
> 

The .so is allowed to have undefined symbols, not the executable iirc.

> However, this information is (partially?) discarded.
> 
> Create a .so with void foo(); in it, then write a program to link to the .so.
> 
> Recompile the .so with foo() missing.
> 
> Run the program.
> 
> What happens is that you get a link error at the first call to foo().
> It appears that the linker doesn't even bother to link functions until
> they're first called (presumably by using some trap).
> 
> At least that was the rather unexpected behaviour I encountered last
> time I messed up my .so's.
> 

Not really, ELF allows lazy binding.

> Is this in any way related to delay loading of DLLs?

Same idea, but different implementation.