ZeroMQ
ZeroMQ core engine in C++, implements ZMTP/3.1
... as asynchronous message-processing tasks. It has a score of language APIs and runs on most operating systems. Libzmq is mainly written in C++98 with some optional C++11-fragments. For configuration either autotools or CMake is employed. For Linux users, pre-built binary packages are available for most distributions. Note that DRAFT APIs can change at any time without warning, pick a STABLE build to avoid having them enabled.