Re: [gentoo-alt] Adventures with Prefix on AIX 5.3

[Michael Haubenwallner]

On 12/14/2010 05:23 PM, Perry Smith wrote:
>>>> Drawback 1:
>>>> It is impossible to specify undefined symbols in an import file for the
>>>> shared object to allow for subsequent link steps keeping those symbols in the
>>>> created shared object or executables, to be resolved by runtime linking when
>>>> the executable is run.
>
>
> Can you describe the original, base, issue?  I'm wondering if there is some confusing between
> import files and export files.  I think a specific example would help me to understand.
> This may not be worth the time since it sounds like from your comment that, over time,
> this issue should go away but I'm still curious.

Trying to create a sample from memory:

Sources:

  $ cat a.c
  int afunc(void) { return 0; }

  $ cat b.c
  extern int afunc(void);
  int bfunc(void) { return afunc() + 1; }

(optional):
  $ cat c.c
  int cfunc(void) { return 2; }

  $ cat main.c
  extern int bfunc(void);
  int main(void) { return bfunc(); }

Actions:

*) Create a shared object 'a':
   from a.c,
   with runtime linking enabled,
   loaded at runtime as (something like) 'a0'.

*) Create a shared object 'b':
   from b.c,
   with runtime linking enabled,
   /without/ linking against 'a' (results in 'afunc' being undefined),
   loaded at runtime as (something like) 'b0'.

*) Create an executable 'exe':
   from main.c,
   linking against 'a' (without any version number),
   linking against 'b' (without any version number),
   at runtime loading 'a0' (with some version number),
   at runtime loading 'b0' (with some version number).

The exakt names for linktime and runtime are less important - they just have to be different.
However, for linktime it should be something like 'liba.so'.

The important problem when creating 'exe' is:

How to automagically have 'b' tell the linker that it has an undefined symbol 'afunc',
so that the reference to 'a0' is added to 'exe'.

As far as I have seen, this problem is irrelevant to the LIBPATH problem.

/haubi/
-- 
Michael Haubenwallner
Gentoo on a different level