GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference

asharkdoctor picture asharkdoctor · Apr 23, 2016 · Viewed 33.6k times · Source

Apologies, I understand questions very similar to this have been asked relatively often, although none of the solutions seem to work for me.When attempting to run any c++ code of a reasonable complexity, I get the above error. The full error message is:

/main: relocation error: ./main: symbol _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC1Ev, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference

running another project, I get a very similar error:

./main: relocation error: ./main: symbol _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC1Ev, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference

I don't actually have any problem with compilation, as these projects both compile fine. This just happens when I try to run the executable. I thought it was an error with my gcc install, so today I reinstalled it, although that did not help at all. I don't really know what to do to fix this, can anyone offer assistance?

This is the Makefile I'm using to compile one of the projects, I feel this is where the error could be:

CC= g++
CFLAGS= -Wall -g -std=c++11 -lX11 -lpthread
OBJS = main.o Board_Tile.o Sliding_Solver.o

main: $(OBJS)
   $(CC) -o $@ $(OBJS)
%.o : %.cc
   $(CC) $(CFLAGS) -c $^

My gcc version is 5.3.0, I'm running Ubuntu 14.0.4.

Answer

strangeqargo picture strangeqargo · Apr 23, 2016

GCC 5.1 or 5.2 (can't remember now, google it) changed C++ ABI. Your standard ubuntu (including libstdc++) is compiled with old ABI.

Your gcc compiler tries to use new ABI. Sometimes it works, most of the time - no.

So, there are 3 ways to compile your code:

1) downgrade gcc

2) add -D_GLIBCXX_USE_CXX11_ABI=0 (cmake example) flag (if you go this way, you should add this flag to every makefile or project you build till you upgrade ubuntu or downgrade gcc)

3) upgrade Ubuntu (tested it, by the way 16.04 goes with new ABI and new gcc by default, I had to ack-grep and remove flag mentioned above from all my pet projects)

also: Understanding GCC 5's _GLIBCXX_USE_CXX11_ABI or the new ABI

P.S. funny thing, the answer is in the question: _ZNSt7__cxx11 : CXX11, though we don't really read error messages.