Is it possible to use a library compiled by visual studio in an application compiled by g++ (mingw) on Windows?
If the library is written in C++ and exposes a C++ interface: no (because the name-mangling differs between g++ and VC++).
If the library is a static library written in C (or with an extern "C" interface): yes, but certain caveats apply.
If the library is a DLL with a C interface: yes, but you'll have to create your own import library.