http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57740
--- Comment #7 from roland at gnu dot org --- (In reply to Jakub Jelinek from comment #6) > Note also that libstdc++.a can be used together with libpthread.so or > libstdc++.so with libpthread.a (g++ -static-libstdc++ etc.). If libstdc++.a had strong references, it would work fine with libpthread.so too. That is the case that IMHO actually matters (-static-libstdc++ is important to avoid DSO dependencies specific to the GCC version, which varies across installations in incompatible ways far more than libc/libpthread versions). libstdc++.so's weak references can never work with libpthread.a unless there are other strong references elsewhere in the link. But I'm hard-pressed to think of a scenario in which someone actually wants libstdc++.so with libpthread.a.
