https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html makes for pretty interesting reading on this topic.
https://youtu.be/Ic4j0ujWL-A looks interesting too. -gmt -gmt Greg Turner g...@be-evil.net On Mon, Nov 30, 2015 at 3:31 AM, Anthony G. Basile <bluen...@gentoo.org> wrote: > On 11/30/15 6:17 AM, Anthony G. Basile wrote: >> different direction: what about building with >> rpath=/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/ and then making sure that >> portage respects that library file during any --depclean or >> @preserved-rebuild? i'm not sure how we'd >> inject LDFLAGS=-Wl,-rpath=... consistantly and sanely into all c++ builds. >> >> this would solve all problems i can see: 1) gcc-config reshuffles >> /etc/ld.so.conf.d/05gcc-<tuple>.conf but rpath takes presidence, 2) the >> correct library symbols are guaranteed to be there in both exe and lib. >> 3) it pro-actively guards against abi mismatches when switching gcc even >> for other languages like fortran, java, obj-c. > > oh i should add that we don't support switching back and forth between > c++98 and c++11. which is used is an upstream choice via whatever -std= > they add to the build system, otherwise we go with the compiler default. > > i'm going to play with situations like foo is built using > c++{98,11}/gcc-4.{8,9} and links against libbar built using > c++{98,11}/gcc-4.{8,9} and libbas similarly built using the rpath > technique and see what kind of wierdness i might hit. i stil think it > will work. > > -- > Anthony G. Basile, Ph.D. > Gentoo Linux Developer [Hardened] > E-Mail : bluen...@gentoo.org > GnuPG FP : 1FED FAD9 D82C 52A5 3BAB DC79 9384 FA6E F52D 4BBA > GnuPG ID : F52D4BBA > >
