Re: What happened to libtool transitive DSOs?

[Tim Mooney]

In regard to: Re: What happened to libtool transitive DSOs?, Bob...:

> On Thu, 21 Jun 2018, John Calcote wrote:
>
> > Hi Bob. It's an ubuntu distro release - Linux Mint 18. Why would they do
> > that?
>
> GNU Linux and the GNU linker support implicit library dependencies.

Sorry to jump into this discussion late, but I wanted to point out
that at least RHEL seems to be moving away from using implicit library
dependencies.

In the RHEL 7.5 (current latest) release notes, chapter 53, on deprecated
functionality:

        
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/7.5_release_notes/chap-red_hat_enterprise_linux-7.5_release_notes-deprecated_functionality

there's this note:

Symbols from libraries linked as dependencies no longer resolved by ld

Previously, the ld linker resolved any symbols present in any linked
library, even if some libraries were linked only implicitly as
dependencies of other libraries. This allowed developers to use symbols
from the implicitly linked libraries in application code and omit
explicitly specifying these libraries for linking.

For security reasons, ld has been changed to not resolve references to
symbols in libraries linked implicitly as dependencies.

As a result, linking with ld fails when application code attempts to use
symbols from libraries not declared for linking and linked only implicitly
as dependencies. To use symbols from libraries linked as dependencies,
developers must explicitly link against these libraries as well.

To restore the previous behavior of ld, use the -copy-dt-needed-entries
command-line option. (BZ#1292230)


----- end excerpt from RHEL release notes

Tim
--
Tim Mooney                                             address@hidden
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