Undefined reference to 'dlsym'

c++, compiler-errors, gcc, ubuntu-13.10

Solution

I have found the solution; passing the `-Wl,--no-as-needed` flag to ld before `-ldl`. The new compile command is:

gcc main.cpp -lsqlapi -lstdc++ -Wl,--no-as-needed -ldl

Apparently it has something to do with recent versions of gcc/ld linking with `--as-needed` by default.

Problem

I have seen a lot of similar posts, but tried every trick in the book and am still struggling. Everything was working fine, but after installing/removing wireshark with some components/disselectors it all got messed up. I don't remember exactly which libraries/packages got uninstalled, but probably a lot more than I noticed. If I create a simple main.cpp file like this one: ``` #include <SQLAPI.h> int main() { SAConnection con; return 0; } ``` and try g++ main.cpp -lsqlapi -ldl it gives me the following error messages: ``` /usr/local/lib/libsqlapi.so: undefined reference to `dlsym' /usr/local/lib/libsqlapi.so: undefined reference to `dlerror' /usr/local/lib/libsqlapi.so: undefined reference to `dlopen' /usr/local/lib/libsqlapi.so: undefined reference to `dlclose' collect2: error: ld returned 1 exit status ``` I have tried to put -ldl before -lsqlapi as some have suggested that the order is important. If I use gcc instead of g++ the error is: ``` /usr/bin/ld: /tmp/ccwBI4tj.o: undefined reference to symbol '__gxx_personality_v0@@CXXABI_1.3' /usr/lib/x86_64-linux-gnu/libstdc++.so.6: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status ``` I am able to compile and run the file if SAConnection is removed. I don't think it has anything to do with SQLAPI, because I experience similar problems with libboost. I don't have a small code example, but when I compile a project that was successfully compiled last week, I get the error: ``` /usr/bin/ld: debug/components/helloworld/HelloWorld.o: undefined reference to symbol '_ZN5boost6system15system_categoryEv' /usr/lib/x86_64-linux-gnu/libboost_system.so.1.53.0: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status ``` This project is using a Makefile that has been unchanged, so it has to be something on my system that is not correct. I have tried to reinstall build-essential. Using Ubuntu 64 bit 13.10 with g++ version 4.8.1.

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