Choice of language for portable library
c, c++, multiplatform, portability
Solution
You can use either C or C++ for the implementation, but I would recommend to define the interface in pure C. It will be much easier to integrate.
Problem
I want to write a library which will be dynamically linked from other programs running on modern operating systems like Windows, Linux and OS/X (i.e. it will be deployed as a `.dll` or `.so` module). What is the most appropriate language in that case? Should I stick with plain C? Or is C++ also ok?