#define TCON(decls) struct { decls; } _tcon[1]
#endif
+/**
+ * TCON_WRAP - declare a wrapper type containing a base type and type canaries
+ * @basetype: the base type to wrap
+ * @decls: the semi-colon separated list of type canaries.
+ *
+ * This expands to a new type which includes the given base type, and
+ * also type canaries, similar to those created with TCON.
+ *
+ * The embedded base type value can be accessed using tcon_unwrap().
+ *
+ * Differences from using TCON()
+ * - The wrapper type will take either the size of the base type, or
+ * the size of a single pointer, whichever is greater (regardless of
+ * compiler)
+ * - A TCON_WRAP type may be included in another structure, and need
+ * not be the last element.
+ *
+ * A type of "void *" will allow tcon_check() to pass on any (pointer) type.
+ *
+ * Example:
+ * // Simply typesafe linked list.
+ * struct list_head {
+ * struct list_head *prev, *next;
+ * };
+ *
+ * typedef TCON_WRAP(struct list_head, char *canary) string_list_t;
+ *
+ * // More complex: mapping from one type to another.
+ * struct map {
+ * void *contents;
+ * };
+ *
+ * typedef TCON_WRAP(struct map, char *charp_canary; int int_canary)
+ * int_to_string_map_t;
+ */
+#define TCON_WRAP(basetype, decls) \
+ union { \
+ basetype _base; \
+ struct { \
+ decls; \
+ } *_tcon; \
+ }
+
+/**
+ * TCON_WRAP_INIT - an initializer for a variable declared with TCON_WRAP
+ * @...: Initializer for the base type (treated as variadic so commas
+ * can be included)
+ *
+ * Converts converts an initializer suitable for a base type into one
+ * suitable for that type wrapped with TCON_WRAP.
+ *
+ * Example:
+ * TCON_WRAP(int, char *canary) canaried_int = TCON_WRAP_INIT(17);
+ */
+#define TCON_WRAP_INIT(...) \
+ { ._base = __VA_ARGS__, }
+
+/**
+ * tcon_unwrap - Access the base type of a TCON_WRAP
+ * @ptr: pointer to an object declared with TCON_WRAP
+ *
+ * tcon_unwrap() returns a pointer to the base type of the TCON_WRAP()
+ * object pointer to by @ptr.
+ *
+ * Example:
+ * TCON_WRAP(int, char *canary) canaried_int;
+ *
+ * *tcon_unwrap(&canaried_int) = 17;
+ */
+#define tcon_unwrap(ptr) (&((ptr)->_base))
+
/**
* tcon_check - typecheck a typed container
* @x: the structure containing the TCON.