Re: [module-init-tools] fix weak symbol handling

[Richard Henderson <rth@twiddle.net>]

On Fri, Jan 17, 2003 at 12:57:03PM +1100, Rusty Russell wrote:
> > No.  The semantics I need is if A references a weak symbol S 
> > and *no one* implements it, then S resolves to NULL.
> 
> Sorry, I was unclear.  I want to know the dependency semantics:
> 
> If B exports S, should depmod believe A needs B, or not?  Your patch
> leaves that semantic (all it does is suppress the errors).

Well, that depends on whether A defines S or not.  If A does
define S, then I don't care.  I'd say "no", A does not depend
on B.  If A does not define S, then most definitely "yes", as
with any other definition.

> I'm not sure what semantics are "right", since I don't know what
> you're trying to do, or what is wrong with get_symbol().

I just told you.  Quoted again above.  Perhaps the following
dummy module will make things even clearer.

---
#include <linux/module.h>
#include <linux/init.h>

extern int not_defined __attribute__((weak));

static int init(void)
{
  return &not_defined ? -EINVAL : 0;
}

static void fini(void)
{
}

module_init(init);
module_exit(fini);
---

You should be able to load this module.


r~