On 30 March 2011 11:04, Dmitry Risenberg wrote: > Hello list! > > After switching from g++-4.4 to g++-4.5, my code stopped compiling and > began reporting errors on linking. > Here's an example (as is, could not reproduce the error on purpose in > small example) - parts of the application are compiled as static > libraries and then linked together with main.cpp.o and shared > libraries: > <...> > /usr/local/bin/c++ -Wall -g > CMakeFiles/test_backend.dir/main.cpp.o -o test_backend -rdynamic > liblibtest_backend.a /usr/local/lib/liblog4cplus.so > /usr/local/lib/libpion-net.so /usr/local/lib/libpion-common.so > -lboost_regex-mt -lpthread -lxml2 -lboost_program_options-mt > -lboost_filesystem-mt -lboost_thread-mt /usr/local/lib/libboost_xml.so > -lboost_system-mt ../Utils/liblibsearch_utils.a > /usr/local/lib/libcurlpp.so -lxslt ../SearchData/liblibsearch_data.a > -lboost_filesystem-mt -Wl,-rpath,/usr/local/lib: > > The reported error is: > /usr/bin/ld: liblibtest_backend.a(DocumentGeneratorService.cpp.o): > undefined reference to symbol 'SSL_write@@OPENSSL_0.9.8' > /usr/bin/ld: note: 'SSL_write@@OPENSSL_0.9.8' is defined in DSO > //lib64/libssl.so.0.9.8 so try adding it to the linker command line > //lib64/libssl.so.0.9.8: could not read symbols: Invalid operation > > OK, adding -lssl to the linking list fixes that, but another similar > error occurs - looks like I'll have to add all dependent shared > libraries to the list to fix that, so there should be a better way. > > Adding --verbose option to compilcation, I get the following output: > <...> > COLLECT_GCC_OPTIONS='-v' '-Wall' '-g' '-o' 'test_backend' '-rdynamic' > '-shared-libgcc' '-mtune=generic' '-march=x86-64' > /usr/lib/gcc/x86_64-linux-gnu/4.5.1/collect2 --build-id > --no-add-needed --eh-frame-hdr -m elf_x86_64 --hash-style=gnu > -export-dynamic -dynamic-linker /lib64/ld-linux-x86-64.so.2 -z relro > -o test_backend > /usr/lib/gcc/x86_64-linux-gnu/4.5.1/../../../../lib64/crt1.o > /usr/lib/gcc/x86_64-linux-gnu/4.5.1/../../../../lib64/crti.o > /usr/lib/gcc/x86_64-linux-gnu/4.5.1/crtbegin.o > -L/usr/lib/gcc/x86_64-linux-gnu/4.5.1 > -L/usr/lib/gcc/x86_64-linux-gnu/4.5.1/../../../../lib64 > -L/lib/../lib64 -L/usr/lib/../lib64 > -L/usr/lib/gcc/x86_64-linux-gnu/4.5.1/../../.. > -L/usr/lib/x86_64-linux-gnu CMakeFiles/test_backend.dir/main.cpp.o > liblibtest_backend.a /usr/local/lib/liblog4cplus.so > /usr/local/lib/libpion-net.so /usr/local/lib/libpion-common.so > -lboost_regex-mt -lpthread -lxml2 -lboost_program_options-mt > -lboost_filesystem-mt -lboost_thread-mt /usr/local/lib/libboost_xml.so > -lboost_system-mt ../Utils/liblibsearch_utils.a > /usr/local/lib/libcurlpp.so -lxslt ../SearchData/liblibsearch_data.a > -lboost_filesystem-mt -rpath /usr/local/lib: -lstdc++ -lm -lgcc_s > -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/x86_64-linux-gnu/4.5.1/crtend.o > /usr/lib/gcc/x86_64-linux-gnu/4.5.1/../../../../lib64/crtn.o > > OK, --no-add-needed is the offending option and removing it fixes the > linking. But why did it get there? While I can disable it via > -Wl,--add-needed, I want to know the root cause for this error and fix > it. > > My system is Linux 2.6.35 (Ubuntu Maverick), gcc (Ubuntu/Linaro > 4.5.1-7ubuntu2) 4.5.1. Looks like a change in Ubuntu's GCC package: https://lists.ubuntu.com/archives/ubuntu-devel/2010-November/031991.html
