Re: shared library from smaller pieces

[Ralf Wildenhues]

Hi Vlad,

* Vlad Skvortsov wrote on Sun, Dec 04, 2005 at 08:01:45AM CET:
> 
> I use automake/libtool environment for a project with couple of dozens 
> of libraries. I link those libraries statically into the binaries that 
> are then distributed. It works ok.
> 
> What I need now is to create a shared library that would contain a 
> subset of those smaller libraries. Say, I want to pack the contents of 
> libaaa.la, libbbb.la and libccc.la into libbig, and libbig has to be 
> shared (it will be distributed in binary form).
> 
> When I use something like this:
> 
> lib_LT_LIBRARIES = libbig.la
> libbig_la_LIBADD = .../libaaa.la .../libbbb.la .../libccc.la
> 
> I end up with the shared library that contains _references_ to _shared_ 
> libraries aaa, bbb and ccc. But I just want their contents to be packed 
> inside.
> 
> How can I achieve that?

You make the other libraries into `convenience archives'.  These are
documented in both
  info Automake 'A Shared Library'
  info Libtool 'Static libraries'

Short: noinst_LTLIBRARIES creates these, they contain objects with PIC
code.  You'd do:

  noinst_LTLIBRARIES = libaaa.la libbbb.la libccc.la
  lib_LTLIBRARIES = libbig.la
  libbig_la_LIBADD = ./libaaa.la ./libbbb.la ./libccc.la

Now I guess you *also* want to build the program as will, with the stuff
linked in statically.  You *can* do

  bin_PROGRAMS = foo
  foo_LDADD = ./libaaa.la ./libbbb.la ./libccc.la

and it will likely work fine, on many platforms.  *However*:  It's not
totally portable, it will actually link PIC objects into your program,
thus the program will be a bit slower than with non-PIC objects, and
of course you should not let foo get anywhere close to libbig, as then
you'll have fun with duplicate symbols.

Does that help you?

Cheers,
Ralf