+It is conventional to form the name of an array type by appending
+.RB ` _v '
+to the base type name. If the base type is a standard type, or is
+declared separately from the array, it's also conventional to declare a
+macro with the same name as the array type only in uppercase which may
+be used to prevent multiple declarations, e.g.,
+.VS
+#ifndef FOO_V
+# define FOO_V
+ DA_DECL(foo_v, foo);
+#endif
+.VE