tcon: add test case for const members.

[ccan] / ccan / tcon / tcon.h

diff --git a/ccan/tcon/tcon.h b/ccan/tcon/tcon.h
index 1dbadafc9726716e6d19d82794ab22b461ef4903..e0f84b383976c4d106e6d9fe3ee9043c449d1ed8 100644 (file)
--- a/ccan/tcon/tcon.h
+++ b/ccan/tcon/tcon.h
@@ -321,6 +321,8 @@
  * tcon_container_of() evaluates to a pointer to the container
  * structure.  With sufficient compiler support, the pointer will be
  * correctly typed, and the type of @member_ptr will be verified.
+ * Note that const is discarded; a const @member_ptr still yields a
+ * non-const container (unless @canary is const).
  *
  * Returns NULL if @member_ptr is NULL.
  */
@@ -330,7 +332,7 @@
                canary, tcon_container_of_((member_ptr),                \
                                           tcon_offset((x), canary)))
 
-static inline void *tcon_container_of_(void *member_ptr, size_t offset)
+static inline void *tcon_container_of_(const void *member_ptr, size_t offset)
 {
        return member_ptr ? (char *)member_ptr - offset : NULL;
 }