+1. My thoughts exactly. One of the factors I reject C++ library for my pet projects is that I can't interface them easily with FFI (LuaJIT, Common Lisp CFFI, Python CTypes, etc.).
And one think that I love about ZeroMQ, is that even being C++ it exposes the stuff with extern "C" and makes life easier. I wish Qt, wxWidgets were easier to expose this way (okay, there is SWIG, or some other tools luabind, etc. - but they produce additional DLL/.so files that are sometimes as big as the library they are wrapping (if not bigger)).
And one think that I love about ZeroMQ, is that even being C++ it exposes the stuff with extern "C" and makes life easier. I wish Qt, wxWidgets were easier to expose this way (okay, there is SWIG, or some other tools luabind, etc. - but they produce additional DLL/.so files that are sometimes as big as the library they are wrapping (if not bigger)).