Error libc++.so: undefined reference to `_Unwind_GetRegionStart'

Question

I'm trying to have my first embryo of C++ compiled with clang++-4.0

my code:

//main.cpp
#include <iostream>

// this line is to deal with the link error:
// "undefined reference to symbol '__cxa_thread_atexit@@CXXABI..."
// cf. http://stackoverflow.com/q/29322666/356440
extern "C" int __cxa_thread_atexit(void (*func)(), void *obj,
                                   void *dso_symbol) {
  int __cxa_thread_atexit_impl(void (*)(), void *, void *);
  return __cxa_thread_atexit_impl(func, obj, dso_symbol);
}

int main ()
{
    return 0;
}

and I compile with clang++-4.0, and link with ld this way:

clang++-4.0 -c main.cpp -o main.o
ld -o test main.o -lc++ -lc++abi -lc

It's as if I'm missing to link with another library, but I don't know which one or ones.

Do you see what's wrong or missing ? I think I'm missing some beginner stuff for doing c++ stuffs with clang++ on linux.

Compilation errors:

ld: warning: cannot find entry symbol _start; defaulting to 0000000000400380 main.o: In function __cxx_global_var_init': main.cpp:(.text.startup+0x13): undefined reference tostd::ios_base::Init::Init()' main.cpp:(.text.startup+0x19): undefined reference to std::ios_base::Init::~Init()' main.cpp:(.text.startup+0x2d): undefined reference to__dso_handle' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to _Unwind_GetRegionStart' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to_Unwind_RaiseException' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to _Unwind_SetIP' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to_Unwind_GetLanguageSpecificData' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to _Unwind_Resume' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to_Unwind_GetIP' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to _Unwind_SetGR' //usr/lib/x86_64-linux-gnu/libc++.so: undefined reference to_Unwind_DeleteException'

Possible dublicate of [What is an undefined reference/unresolved external symbol error and how do I fix it?](http://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix) — πάντα ῥεῖ, May 14 '17 at 22:04
@πάνταῥεῖ I don't think it's a dupplicate. Here the undefined reference is not linked to my code. Here I try to compile a main function that simply returns 0... nothing else... — Stephane Rolland, May 14 '17 at 22:07
What happens when you add `-lcpp` _at the end_ of the command line? Is this a version of `clang` installed via a package manager, or did you build it from source? — Qix - MONICA WAS MISTREATED, May 15 '17 at 08:56
installed via package manager, with apt.llvm.org added to my apt sourcelist. When I add at linking `-lcpp`, `ld` complains it doesn't know about it. — Stephane Rolland, May 15 '17 at 09:30

score 1 · Accepted Answer · answered May 15 '17 at 09:35

1

You should not link C++ applications with ld. Link with the C++ compiler executable because it links in all the necessary libraries:

clang++-4.0 -c main.cpp -o main.o
clang++-4.0 -o test main.o

answered May 15 '17 at 09:35

Maxim Egorushkin

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Error libc++.so: undefined reference to `_Unwind_GetRegionStart'

1 Answers1