This code #include <string> #include <istream> #include <iostream> #include <vector> typedef std::vector<unsigned char> Signature; namespace foo { bool bar (const std::string& input, const Signature& signature, std::istream& key) { return true; } } when compiled with g++ -fPIC -o global_noans.so -shared -static-libgcc -static-libstdc++ -Wl,-h,global.so -fuse-ld=gold global_noans.cpp produces this nm output 0000000000082745 T _ZN3foo3barERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKSt6vectorIhSaIhEERSi Notice how it is a global symbol? On the other hand, this code#include <string> #include <istream> #include <iostream> #include <vector> typedef std::vector<unsigned char> Signature; namespace foo { namespace { bool bar(const std::string& input, const Signature& signature, std::istream& key) { return true; } } } when compiled with g++ -fPIC -o global.so -shared -static-libgcc -static-libstdc++ -Wl,-h,global.so -fuse-ld=gold global.cpp produces this nm output 00000000000826b5 t _ZN3foo12_GLOBAL__N_13barERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKSt6vectorIhSaIhEERSi And now we note the symbolis local. I tried building the shared library with a -Wl,--version-script=global.map, where global.map is set up to make the symbol glocal instead of local, and that did not work. I also tried compiling the source code with void __attribute__ ((visibility ("default"))) but that made no difference, either, in the anonymous namespace symbol being lobal. I have pinged the binutils list and they said this might be a g++ version issue (I am using GCC 8.3.0 with binutils 2.34, gold linker). If this is a g++ issues, I am assuming the issue is anonymous name spaces make the symbol local, but if that isn't the cause, I'll got back to the binutils folks. I am also going to try a later version of GCC and binutils. Thanks, TOm