This is a POSIX binding for LuaJIT, Lua 5.1, 5.2, 5.3 and 5.4; like most libraries, it simply binds to C APIs on the underlying system, so it won't work on non-POSIX systems. However, it does try to detect the level of POSIX conformance of the underlying system and bind only available APIs. For a while, luaposix contained support for curses functionality too, but now that has its own lcurses repository again, where it is being maintained separately.