RoddyP 0 Posted June 10, 2022 (edited) Oops. The problem was easily sorted and was actually a _DEBUG vs. NDEBUG mismatch... I'm using C++Builder 11.1 with Clang 64-bit compiler. I have a 64-bit application and a static library both built using the above. When I add the static library to the app and link, I get warnings like this: [ilink64 Warning] Warning: Public symbol 'boost::filesystem::codecvt_error_category()' defined in both module C:\...\LIBBOOST_FILESYSTEM-BCB64-MT-S-X64-1_70.A|codecvt_error_category.o and C:\...\LIBBOOST_FILESYSTEM-BCB64-MT-SD-X64-1_70.A|codecvt_error_category.o It looks like the app must be requiring the non-static version of Boost, while the library is using the static one, or vice-versa, but I can't find any way of changing this in C++Builder project options. Edited June 11, 2022 by RoddyP Share this post Link to post