It's a bit dated now, but loris is a good example; a sophisticated sound modeling library. Written in C++ with a procedural interface in C and a scripting interface in python:

http://www.hakenaudio.com/Loris/#doc

cheers,
Rich

On Fri, Mar 2, 2012 at 11:32 PM, katja <katjavetter@gmail.com> wrote:

Can anyone point me to an example of a C++ lib with C API, in the
field of dsp? Not sure if I can think of the best way how to do it.