On Sat, 24 Sept 2022 at 11:18, Jonathan Wakely wrote: > If you won't do that, I would figure out why the libraries in /usr/libx86_64-linux-gnu/4.4.3 are even being considered by the linker. That's not a standard system path, so GCC 4.9.4 should not be looking in there. > > Compile with -v and -Wl,v -Wl,t to see wht paths are being passed to the linker, and which files the linker is looking at. Try that when compiling a C program, and when compiling a C++ program. Check that the 'gcc' nd 'g++' binaries are consistent. It sounds to me like you might have created some kind of hybrid of GCC 4.4.2 and 4.9.4! And if none of that works, show us **exactly** the configure command you're using, and the output of 'gcc -v' for all existing GCC installations on the system, so we can see what's actually happening. It's hard to debug it from your descriptions so far.