On 19.10.21 08:26, Gavin Lambert via Boost wrote:
Header-only does not avoid ABI ODR problems. It just moves where they occur (which in some ways makes them a lot worse than built libraries).
ODR violations can be prevented with namespace aliases. #if __cplusplus >= 201703L #define BOOST_JSON_NAMESPACE json_with_std_string_view namespace BOOST_JSON_NAMESPACE { using string_view = std::string_view; } #else #define BOOST_JSON_NAMESPACE json_with_boost_string_view namespace BOOST_JSON_NAMESPACE { using string_view = boost::string_view; } #endif using json = BOOST_JSON_NAMESPACE; namespace BOOST_JSON_NAMESPACE { // Library contents go here. } That said, compiling parts of the same program with different C++ standards is asking for trouble. I would expect ODR violations from the standard library in that case. -- Rainer Deyke (rainerd@eldwood.com)