+
+/**
+ * UNUSED - a parameter is unused
+ *
+ * Some compilers (eg. gcc with -W or -Wunused) warn about unused
+ * function parameters. This suppresses such warnings and indicates
+ * to the reader that it's deliberate.
+ *
+ * Example:
+ * // This is used as a callback, so needs to have this prototype.
+ * static int some_callback(void *unused UNUSED)
+ * {
+ * return 0;
+ * }
+ */
+#define UNUSED __attribute__((unused))