Re: [EXTERNAL] Re: Q: library dependencies

On Fri, Sep 25, 2020 at 11:38 AM Nick Bowler <[email protected]> wrote:

> On 2020-09-25, John Calcote <[email protected]> wrote:
> > On Fri, Sep 25, 2020 at 10:45 AM Bob Friesenhahn <
> [email protected]> wrote:
> >> Exactly!  It might as well be a tar file except that the 'ar' archiver
> >> knows how to add/update/remove files from it and that is not possible
> >> with a tar file.  The ability to do incremental updates of the archive
> >> file is important as objects are built/rebuilt.  The 'make' program
> >> itself already understands archive files.
> >>
> >
> > I did not know this about libtool and convenience libraries. Do you have
> > any historical notion of why this was done? I ask because this sort of
> > behaviour total defeats the linker's ability to discard unused objects,
> > does it not?
>
> As I mentioned elsethread, at least with current versions, this only
> appears to actually happen when convenience libraries are linked into
> libraries (which OP is doing).  This _has_ to happen for the use case
> that convenience libraries are described to be, well, convenient for:
> linking a set of common object files into multiple shared libraries.
>
> Thanks Nick - that clears up my confusion and makes perfect sense. Sorry I
missed your earlier comments on it.

John