Add luajit snippet

snippet/luajit/luaffi.lua

@@ -0,0 +1,31 @@
+-- 调用 C 函数
+local ffi = require("ffi")
+ffi.cdef([[
+int printf(const char *fmt, ...);
+]])
+
+ffi.C.printf("Invocate printf in %s\n", "lua")
+
+ffi.cdef[[
+void Sleep(int ms);
+int poll(struct pollfd *fds, unsigned long nfds, int timeout);
+]]
+
+local sleep
+if ffi.os == "Windows" then
+  function sleep(s)
+    ffi.C.Sleep(s*1000)
+  end
+else
+  function sleep(s)
+    ffi.C.poll(nil, 0, s*1000)
+  end
+end
+
+for _ = 1, 160 do
+  io.write(".")
+  io.flush()
+  sleep(0.01)
+end
+io.write("\n")
+