https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66438
James Y Knight <foom at fuhm dot net> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |UNCONFIRMED Resolution|INVALID |--- --- Comment #5 from James Y Knight <foom at fuhm dot net> --- Sorry, please try again. Andreas Schwab: I did compile it with the libstdc++ that came with the compiler -- and then I upgraded the binary libstdc++.so to the newer one that came with gcc 5. And it broken. Thus the report of breaking binary compat. (It also happens with new compiles in Debian because of what Gianfranco says) Andrew Pinski: The *one and only purpose* of the file libstdc++-v3/src/c++11/compatibility-c++0x.cc is to provide binary compatibility for c++11 binaries compiled against older libstdc++ versions, and now running against a newer one. If libstdc++.so.6, version 5.1, is not supposed to work properly with c++ binaries compiled by the 4.9 compiler, it should not be providing these compatibility symbols at all. Since it does provide them, there is clearly intent to provide compatibility so, it ought to work. Or they should be deleted...