Re: [Boost-users] libboost_date_time: undefined reference to__sync_fetch_and_add_4

Carsten Raas:

Yes, these headers include atomicity.h. But they don't trigger the problem directly:

#include <iostream> #include <string> #include <istream> int main() { std::string s="test"; std::cout << s << std::endl; }

Works fine, if compiled with Intel icpc.

If <string> uses reference counting, it will use __sync_fetch_and_add on copy: #include <string> int main() { std::string s="test"; std::string s2( s ); } The use in <istream> is probably triggered by installing a locale facet, something the DateTime library does.