--- /dev/null
+#include <ccan/typesafe_cb/typesafe_cb.h>
+#include <stdlib.h>
+
+/* const args in callbacks should be OK. */
+
+static void _register_callback(void (*cb)(void *arg), void *arg)
+{
+}
+
+#define register_callback(cb, arg) \
+ _register_callback(typesafe_cb(void, (cb), (arg)), (arg))
+
+static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg)
+{
+}
+
+#define register_callback_pre(cb, arg) \
+ _register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg))
+
+static void _register_callback_post(void (*cb)(void *arg, int x), void *arg)
+{
+}
+
+#define register_callback_post(cb, arg) \
+ _register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg))
+
+struct undefined;
+
+static void my_callback(const struct undefined *undef)
+{
+}
+
+static void my_callback_pre(int x, struct undefined *undef)
+{
+}
+
+static void my_callback_post(struct undefined *undef, int x)
+{
+}
+
+int main(int argc, char *argv[])
+{
+ struct undefined *handle = NULL;
+ void (*cb)(const struct undefined *undef) = my_callback;
+ void (*pre)(int x, struct undefined *undef) = my_callback_pre;
+ void (*post)(struct undefined *undef, int x) = my_callback_post;
+
+ register_callback(cb, handle);
+ register_callback_pre(pre, handle);
+ register_callback_post(post, handle);
+ return 0;
+}
*
* This macro is used to create functions which allow multiple types.
* The result of this macro is used somewhere that a @desttype type is
- * expected: if @expr was of type @oktype, it will be cast to
- * @desttype type. As a result, if @expr is any type other than
- * @oktype or @desttype, a compiler warning will be issued.
+ * expected: if @test is exactly of type @oktype, then @expr will be
+ * cast to @desttype type, otherwise left alone.
*
* This macro can be used in static initializers.
*
* _set_some_value(cast_if_type(void *, (e), (e), unsigned long))
*/
#define cast_if_type(desttype, expr, test, oktype) \
-__builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), \
+ __builtin_choose_expr(__builtin_types_compatible_p(typeof(test), oktype), \
(desttype)(expr), (expr))
#else
#define cast_if_type(desttype, expr, test, oktype) ((desttype)(expr))
* #define register_callback(fn, arg) \
* _register_callback(typesafe_cb_const(void, (fn), (arg)), (arg))
*/
-#define typesafe_cb_const(rtype, fn, arg) \
- sizeof((fn)((const void *)0)), \
- cast_if_type(rtype (*)(const void *), \
- (fn), (fn)(arg), rtype (*)(typeof(arg)))
+#define typesafe_cb_const(rtype, fn, arg) \
+ cast_if_type(rtype (*)(const void *), (fn), (fn)(arg), rtype)
/**
* typesafe_cb_preargs - cast a callback function if it matches the arg
* (arg))
*/
#define typesafe_cb_preargs(rtype, fn, arg, ...) \
- cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), (fn), \
+ cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), &*(fn), \
rtype (*)(__VA_ARGS__, typeof(arg)))
+
/**
* typesafe_cb_postargs - cast a callback function if it matches the arg
* @rtype: the return type of the callback function
* (arg))
*/
#define typesafe_cb_postargs(rtype, fn, arg, ...) \
- cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), (fn), \
+ cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), &*(fn), \
rtype (*)(typeof(arg), __VA_ARGS__))
+
/**
* typesafe_cb_cmp - cast a compare function if it matches the arg
* @rtype: the return type of the callback function
* typesafe_cb_cmp(int, (cmpfn), (base)), (arg))
*/
#define typesafe_cb_cmp(rtype, cmpfn, arg) \
- cast_if_type(rtype (*)(const void *, const void *), (cmpfn), \
+ cast_if_type(rtype (*)(const void *, const void *), (cmpfn), &*(cmpfn), \
rtype (*)(const typeof(*arg)*, const typeof(*arg)*))
#endif /* CCAN_CAST_IF_TYPE_H */