WOscLib

WOscLib is written in C++ and relased under the GNU LGPL.

(from http://wosclib.sourceforge.net/doc):

This work is a re-implementation and (hopefully) modernization of the the classic OSC-Kit, which was originally provided by Matt-Wright and was written in pure C (see http://www.cnmat.berkeley.edu/OpenSoundControl).
Matt's kit uses lots of global variables, a fast but user-unfriendly memory-allocation (and de-allocation)-scheme, makes use of non type-save osc-callback-functions, has no real exception handling and its modularity is heavily restricted due to the C-design. There is also no documentation based on a modern auto-doc-system (e.g. doxygen) what makes it harder for newbies to get an OSC-system running in 10 minutes since they have to read all (or at least some) source-files first.

Summary of the reasons of the re-implementation are:

Higher level programming language (C++) and therefor a higher productivity.
Enhanced modularity.
Enhanced code-reusage.
Elimination of global variables and functions to facilitate usage of multiple OSC-servers in the same process.
Good exception handling.
Type-save interfaces for OSC arguments in OSC-methods.
Better (and dynamic) management of OSC-methods.
Good documentation.
Less complex OSC-system implementation.