As covered in a previous note, I'm building stdcxx in order to use it as the standard C++ library in Tuscany SDO. Looking at the Configuration Manager pane I cane see 8 different configuration options ie 11d Debug Dll 11s Debug Static 12d Optimized Thread-safe Dll 12s Optimized Thread-safe Static 15d Debug Thread-safe Dll 15s Debug Thread-safe Static 8d Optimized Dll 8s Optimized Static When we build SDO with the Microsoft library we use either "Multi-threaded DLL" (/MD) or "Multi-threaded Debug DLL" (/MDd). Which of the stdcxx configurations correspond to those two. My guess would be to use "12d Optimized Thread-safe Dll" to replace "Multi-threaded DLL" and "15d Debug Thread-safe Dll" to replace "Multi-threaded Debug DLL" Regards, Geoff.