I have a c++ application which I am trying to build under Linux, it needs to be linked to a third party shared library, however this library has been built with a quite recent version of GCC/glibc (4.8.3/2.18). When I try and build my application using a less recent version of GCC/glibc (4.4.7/2.12), the linked phase of the build fails, with ld complaining of undefined references, which are references to functions defined in the newer libstdc++.
The third party has given me a precompiled version of libstdc++ and libgcc_s to use with the library, but how do I use these versions in my build?
How do I tell GCC to use the precompiled libraries instead of the system ones, while still using the system GCC?
I have tried using the "-nodefaultlibs" option and including "-lstdc++" and "-L" options, but it seems to have no effect on the undefined references.
Example of an error I get during linking:
undefined reference to std::__throw_bad_function_call()#GLIBCXX_3.4.14'
undefined reference to std::length_error::~length_error()#GLIBCXX_3.4.15'
I managed to get the application to build successfully by specifying the full path of the libstdc++ and libgcc_s shared objects in the objects list of the linking command (e.g. /home/mike/Downloads/libstdc++.so.6) . Going this way I didn't need to use any additional options such as "-nostdlibs" and only needed to ensure the linked shared objects were available via the LD_LIBRARY_PATH when running the application.
Related
I use c++11, but also some libraries that are not configured for it, and need some type conversion. In particular I need a way to convert std::__cxx11::string to regular std::string, but googling I can't find a way to do this and putting (string) in front does not work.
If I do not convert I get linker errors like this:
undefined reference to `H5::CompType::insertMember(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned long, H5::DataType const&) const'
Is it possible that you are using GCC 5?
If you get linker errors about undefined references to symbols that involve types in the std::__cxx11 namespace or the tag [abi:cxx11] then it probably indicates that you are trying to link together object files that were compiled with different values for the _GLIBCXX_USE_CXX11_ABI macro. This commonly happens when linking to a third-party library that was compiled with an older version of GCC. If the third-party library cannot be rebuilt with the new ABI then you will need to recompile your code with the old ABI.
Source: GCC 5 Release Notes/Dual ABI
Defining the following macro before including any standard library headers should fix your problem: #define _GLIBCXX_USE_CXX11_ABI 0
If you can recompile all incompatible libs you use, do it with compiler option
-D_GLIBCXX_USE_CXX11_ABI=1
and then rebuild your project. If you can't do so, add to your project's makefile compiler option
-D_GLIBCXX_USE_CXX11_ABI=0
The define
#define _GLIBCXX_USE_CXX11_ABI 0/1
is also good but you probably need to add it to all your files while compiler option do it for all files at once.
When I had similar issue it's happened because my lib was build using clang++, and it's linked to libstdc++.so by default on my system. While app binary was build using clang and linked with -lc++ option.
Easiest way to check dependencies is to perform ldd libName.so
To fix it you should use the same library on in app and library.
Easiest way. Build library using clang++ and compile app using clang++. Without extra linking options on both steps. Default stdlib will be used.
Build library with -stdlib=c++ and compile app with -lc++. In this case both library and app will use libc++.so.
Build library without extra options and link binary to -lstdc++. In this case both library and app will use libstdc++.so.
Answers here mostly focus on short way to fix it, but if that does not help, I'll give some steps to check, that helped me (Linux only):
If the linker errors happen when linking other libraries, build those libs with debug symbols ("-g" GCC flag)
List the symbols in the library and grep the symbols that linker complains about (enter the commands in command line):
nm lib_your_problem_library.a | grep functionNameLinkerComplainsAbout
If you got the method signature, proceed to the next step, if you got no symbols instead, mostlikely you stripped off all the symbols from the library and that is why linker can't find them when linking the library. Rebuild the library without stripping ALL the symbols, you can strip debug (strip -S option) symbols if you need.
Use a c++ demangler to understand the method signature, for example, this one
Compare the method signature in the library that you just got with the one you are using in code (check header file as well), if they are different, use the proper header or the proper library or whatever other way you now know to fix it
I got this, the only way I found to fix this was to update all of mingw-64 (I did this using pacman on msys2 for your information).
For me -D_GLIBCXX_USE_CXX11_ABI=0 didn't help.
It works after I linked to C++ libs version instead of gnustl.
I had a similar issue recently while trying to link with the pre-built binaries of hdf5 version 1.10.5 on Ubuntu 16.04. None of the solutions suggested here worked for me, and I was using g++ version 9.1. I found that the best solution is to build the hdf5 library from source. Do not use the pre-built binaries since these were built using gcc 4.9! Instead, download the source code archives from the hdf website for your particular distribution and build the library. It is very easy.
You will also need the compression libraries zlib and szip from here and here, respectively, if you do not already have them on your system.
In my case, I was having a similar problem:
/usr/bin/ld: Bank.cpp:(.text+0x19c): undefined reference to 'Account::SetBank(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)' collect2: error: ld returned 1 exit status
After some researches, I realized that the problem was being generated by the way that Visual Studio Code was compiling the Bank.cpp file. So, to solve that, I just prompted the follow command in order to compile the c++ file sucessful:
g++ Bank.cpp Account.cpp -o Bank
With the command above, It was able to linkage correctly the Header, Implementations and Main c++ files.
OBS: My g++ version: 9.3.0 on Ubuntu 20.04
I've encountered similar problems
It turns out my project was using gcc 7 and g++ 9 and tried to link together object files compiled by those two and it all messed up.
Make sure you use the same compiler versions in all your project.
I'm using Mingw32 compiler to build a C++ app.
I'm passing -nostdlib to the linker because I only want to link the libraries I'm going to actually use.
However I'm running into a problem with the C++ standard library.
When I link with libstdc++ I get the following error:
undefined reference to '_Unwind_SjLj_Register'
So clearly libstdc++ isn't the right library to link with.
Is there any way of seeing what libraries Mingw32 links with by default when building a C++ app?
What libraries are being excluded when the flag -nostdlib is passed to linker?
Thanks.
I have a C++ file a.cpp with the library dependency in the path /home/name/lib and the name of the library abc.so.
I do the compilation as follows:
g++ a.cpp -L/home/name/lib -labc
This compiles the program with no errors.
However while running the program, I get the ERROR:
./a.out: error while loading shared libraries: libabc.so.0: cannot open shared object file: No such file or directory
However if before running the program, I add the library path as
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/name/lib;
and compile and run now, it works fine.
Why am I not able to link the library by giving it from the g++ command?
Because shared object libraries are linked at runtime - you either need to add the location to the library search path (as you've done), place it somewhere within an already existing path (like /usr/lib), or add a symbolic link to an existing library path that links to the location where it exists.
If you want to compile the library in so there is no runtime dependency, you'll need a static library (which would be abc.a) - note that this has numerous downsides, however (if the library is updated, you'll need to recompile your executable to incorporate that update).
Why am I not able to link the library by giving it from the g++ command?
You are able to link, and you did link the library succesfully. Otherwise you would not be able to build executable (in your case a.out). The problem you mixed 2 different things: linking with shared libraries and loading them at runtime. Loading shared libraries is a pretty complex concept and described pretty well here Program-Library-HOWTO read from 3.2.
You are linking dynamically, is the default behavior with GCC. LD_LIBRARY_PATH is used to specify directories where to look for libraries (is a way of enforce using an specific library), read: Program-Library-HOWTO for more info. There is also an ld option -rpath to specify libraries search path for the binary being compiled (this info is written in the binary and only used for that binary, the LD_LIBRARY_PATH affect other apps using the same library, probably expecting a new or old version).
Linking statically is possible (but a little tricky) and no dependency would be required (but sometimes is not recommended, because prevent the update of the dependent libraries, for example for security reason, in static linking your always are using the versions of the libraries you have when compiled the binary).
First, I don't know if there is a solution to my problem at all.
I have the following situation:
I have developed a framework library that depends on several other libraries for specific hardware access, etc.
Until now this framework library was only statically linked against.
For the executable that uses the framework library only the dependencies of code that is actually used by the executable have to be linked. (If I don't access a specific hardware at all I don't have to depend on its associated libraries.)
Now I need to also make a shared object of the framework library. Also the dependencies are available as shared libraries, so there is no need for any static linking.
The problem I have now:
When building an application that links dynamically to the framework library I have to either link all dependencies dynamically to the framework library or the application. (Otherwise I get undefined references complaints from ld)
My questions:
Is there any way to ignore certain shared object dependencies if I know that my application will not use any code of the framework library that depends on this shared object?
Is there any way to do this without or with minimal code changes? (linker / compiler switches)
I also need the static linking as described in the original situation to still work.
Additional Info:
Operating system: Linux (Debian Lenny)
Compiler: gcc-4.3
You can, but you basically have to do all of the dynamic library handling yourself. i.e. dlopen the library, and then look up the symbols you need directly with dlsym.
It will make your code more complicated, how much depends on the interface you've got into the libraries.
From man ld
--as-needed
--no-as-needed
This option affects ELF DT_NEEDED tags for dynamic libraries mentioned on the command line after the --as-needed option. Normally,
the linker will add a DT_NEEDED tag for each dynamic library mentioned on the command line, regardless of whether the library is
actually needed. --as-needed causes a DT_NEEDED tag to only be emitted for a library that satisfies a symbol reference from regular
objects which is undefined at the point that the library was linked, or, if the library is not found in the DT_NEEDED lists of other
libraries linked up to that point, a reference from another dynamic library. --no-as-needed restores the default behaviour.
I haven't used it myself but sounds like what you're looking for.
g++ -o your_app -Wl,--as-needed -lframework -la -lb -lc -Wl,--no-as-needed
Edit (suggested by Hanno)
--warn-unresolved-symbols
If the linker is going to report an unresolved symbol (see the option --unresolved-symbols) it will normally generate an error.
This option makes it generate a warning instead.
I have a problem linking boost.asio. It uses boost.system and the linker errors start with:
/boost_1_39_0/boost/system/error_code.hpp:205: undefined reference to `boost::system::get_system_category()'
which means I need to link boost.system. I already built boost and I have now several lib files.
boost_system-mgw32-d-1_39.dll and lib
libboost_system-mgw34-d-1_39.lib
libboost_system-mgw34-mt-d-1_39.lib
libboost_system-mgw34-sd-1_39.lib
and some more. How do I link them? Which one do I use? Do I copy all of them together?
My system is win32+mingw+eclipse cdt+qt 4.5.2+qt integration for eclipse. I already learned that I need to at a LIBS= section to my .pro file.
Can you give my some hints?
Thank you.
The libraries are named based on whether or not multi-threading support is enabled, static and dynamic linkage, debug and release mode, and more. Here's some details:
http://www.boost.org/doc/libs/1_39_0/more/getting_started/unix-variants.html#library-naming
I'm not sure about eclipse as I don't use it, but with gcc (and mingw) you need to specify both a directory to find the libraries in (-L) and the file to link with. For example, if you wanted to link with the single-threaded debug version:
-L/path/to/libraries -lboost_system-mgw34-sd-1_39