The Pagoda software stack consists of a communication portability layer, GASNet, and productivity layers: UPC++ and Berkeley UPC.
GASNet is a high-performance C-level communication interface that emphasizes performance and portability over ease of use. It is intended for authors of runtime libraries, compiler generated code, and requires just a C99 compiler.
UPC++ is a high-level C++ interface that builds "friendlier" PGAS abstractions above GASNet's communication services. These abstractions may come at some cost in performance (but do not necessarily). UPC++ is a library and requires only a C++11 compliant compiler (or later).
Berkeley UPC is a portable, high-performance implementation of the Unified Parallel C language using GASNet for communication.