> On Aug 2, 2018, at 2:57 AM, Jakub Jelinek <jakub@xxxxxxxxxx> wrote: > >> On Thu, Aug 02, 2018 at 11:45:00AM +0200, Dominique Martinet wrote: >> Wearing a lib developer hat, I don't see how you can make a .pc that >> doesn't overlink if you provide something a bit entangled with other >> libs. >> The problem is that if your headers use any sub-lib type you need to add >> that lib in Requires: so that --cflags will pull that lib's include >> path; and that will in turn add that sub-lib to the linked libs even if >> the program likely doesn't care about it (either because they didn't >> even use that part of your lib, or because all uses of that lib will be >> done through your own anyway so it wasn't required in the first place) > > Then it is clearly a task for pkg-config (and libtool) to handle it better. > If the --libs it provides contains some mandatory and some optionally needed > libraries, then it should differentiate between them and use > -Wl,--push-state,--as-needed ... -Wl,--pop-state > around those that are optionally needed. If all libraries from those tools > are optional, perhaps it should use it always. > > Changing the behavior of say -lpthread on the command line is a bad idea, > many projects really expect it to mean that the mentioned library is linked > in and if it no longer does, it causes silent breakage. Forcing users to do > -Wl,--push-state,--no-as-needed ... -Wl,--pop-state > whenever they really mean to link some library is too hostile. Maybe pkg-config could learn to push state and use —as-needed? Some explicit options in gcc and ld like —link-as-needed=libname and —always-link=libname would be nice, too. It seems that the toolchain folks (like you) want -lpthread and the like to keep working, and the package people want a sane default where symbols are made available but the DT_NEEDED entry is only used if needed. On the other hand, switching to as-needed linking seems like it's a step in the right direction in general, but ISTM it would be much nicer to switch to as-needed direct binding. Do glibc and binutils even support Solaris-style direct binding yet? _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx/message/G56MSHDO6IYQSVQ6RKOH2RASL2N4OIZZ/
