tlist: use ccan/tcon

No real change for users.

ccan/tlist/_info

@@ -9,17 +9,17 @@
  * this extends it so you can create list head types which only accomodate
  * a specific entry type.
  *
- * You use TLIST_TYPE() to define the specific struct tlist_<name>, then use
- * the tlist_* variants of the various list_* operations.
- *
  * Example:
  *	#include <err.h>
  *	#include <stdio.h>
  *	#include <stdlib.h>
  *	#include <ccan/tlist/tlist.h>
  *
- *	// Defines struct tlist_children
- *	TLIST_TYPE(children, struct child);
+ *	// We could use TLIST_TYPE(children, struct child) to define this.
+ *	struct tlist_children {
+ *		struct list_head raw;
+ *		TCON(struct child *canary);
+ *	};
  *	struct parent {
  *		const char *name;
  *		struct tlist_children children;
@@ -66,6 +66,7 @@ int main(int argc, char *argv[])
 
 	if (strcmp(argv[1], "depends") == 0) {
 		printf("ccan/list\n");
+		printf("ccan/tcon\n");
 		return 0;
 	}
 

ccan/tlist/tlist.h

@@ -2,8 +2,8 @@
 #ifndef CCAN_TLIST_H
 #define CCAN_TLIST_H
 #include <ccan/list/list.h>
+#include <ccan/tcon/tcon.h>
 
-#if HAVE_FLEXIBLE_ARRAY_MEMBER
 /**
  * TLIST_TYPE - declare a typed list type (struct tlist)
  * @suffix: the name to use (struct tlist_@suffix)
@@ -27,31 +27,12 @@
  *		struct list_node list;
  *	};
  */
-#define TLIST_TYPE(suffix, type)					\
-	struct tlist_##suffix {						\
-		struct list_head raw;					\
-		const type *tcheck[];					\
+#define TLIST_TYPE(suffix, type)			\
+	struct tlist_##suffix {				\
+		struct list_head raw;			\
+		TCON(type *canary);			\
 	}
 
-/**
- * tlist_raw - access the raw list inside a typed list head.
- * @h: the head of the typed list (struct tlist_@suffix)
- * @test_var: a pointer to the expected element type.
- *
- * This elaborate macro usually causes the compiler to emit a warning
- * if the variable is of an unexpected type.  It is used internally
- * where we need to access the raw underlying list.
- */
-#define tlist_raw(h, test_var) \
-	(sizeof((h)->tcheck[0] == (test_var)) ? &(h)->raw : &(h)->raw)
-#else
-#define TLIST_TYPE(suffix, type)					\
-	struct tlist_##suffix {						\
-		struct list_head raw;					\
-	}
-#define tlist_raw(h, test_var) (&(h)->raw)
-#endif
-
 /**
  * TLIST_INIT - initalizer for an empty tlist
  * @name: the name of the list.
@@ -108,6 +89,17 @@
  */
 #define tlist_init(h) list_head_init(&(h)->raw)
 
+/**
+ * tlist_raw - unwrap the typed list and check the type
+ * @h: the tlist
+ * @expr: the expression to check the type against (not evaluated)
+ *
+ * This macro usually causes the compiler to emit a warning if the
+ * variable is of an unexpected type.  It is used internally where we
+ * need to access the raw underlying list.
+ */
+#define tlist_raw(h, expr) (&tcon_check((h), canary, (expr))->raw)
+
 /**
  * tlist_add - add an entry at the start of a linked list.
  * @h: the tlist to add the node to