Re: Should vtable->dlloader_init be called in lt_dlloader_add?

[Ralf Wildenhues]

* Ralf Wildenhues wrote on Sun, Jan 24, 2010 at 10:36:54AM CET:
> * Peter Rosin wrote on Fri, Jan 22, 2010 at 10:12:11AM CET:
> > As mentioned in another mail, should not lt_dlloader_add
> > call vtable->dlloader_init? That seems appropriate when
> > lt_dlloader_remove calls vtable->dlloade_exit...
> > 
> > Like this (completely untested), just showing what I mean...
> 
> Yes, I think this is an improvement.  It is an API change
> however.  I think we can argue that it is a compatible change,
> since .dlloader_init was undocumented before, and calling it
> a second time needs to be a no-op (we need to fix preopen.c!).

Argl.  Wrong.  The documentation contains:

     /* User modules are responsible for their own initialisation. */
     if (myloader_init () != 0)
       return MYLOADER_INIT_ERROR;
  [...]
     Note that if there is any initialisation required for the loader, it
  must be performed manually before the loader is registered - libltdl
  doesn't handle user loader initialisation.

so we cannot easily change that.  :-/

Invoking the .dlloader_init pointer invokes undefined behavior for
existing code which doesn't initialize this member.  So this would be an
incompatible API change.  I don't think it is worth breaking the API for
this.

Cheers,
Ralf