typesafe: fix warnings with gcc's -Wpointer-arith
authorRusty Russell <rusty@rustcorp.com.au>
Mon, 21 Mar 2011 10:31:35 +0000 (21:01 +1030)
committerRusty Russell <rusty@rustcorp.com.au>
Mon, 21 Mar 2011 10:31:35 +0000 (21:01 +1030)
In particular, avoid doing arithmetic on NULL; decay the function to a
pointer using a trinary conditional instead.

ccan/typesafe_cb/typesafe_cb.h

index 7347b7b2912c20291bfbdd9adfdcbb430334c07c..4bc2e2da9b9249e0b1626ac950846acfe9446109 100644 (file)
  *     #define register_callback(fn, arg) \
  *             _register_callback(typesafe_cb_def(void, (fn), (arg)), (arg))
  */
-#define typesafe_cb_def(rtype, fn, arg)                        \
-       cast_if_any(rtype (*)(void *), (fn), (fn)+0,    \
-                   rtype (*)(typeof(*arg)*),           \
-                   rtype (*)(const typeof(*arg)*),     \
+#define typesafe_cb_def(rtype, fn, arg)                                \
+       cast_if_any(rtype (*)(void *), (fn), 0?(fn):(fn),       \
+                   rtype (*)(typeof(*arg)*),                   \
+                   rtype (*)(const typeof(*arg)*),             \
                    rtype (*)(volatile typeof(*arg)*))
 
 /**
  *             _register_callback(typesafe_cb_exact(void, (fn), (arg)), (arg))
  */
 #define typesafe_cb_exact(rtype, fn, arg)                              \
-       cast_if_type(rtype (*)(void *), (fn), (fn)+0, rtype (*)(typeof(arg)))
+       cast_if_type(rtype (*)(void *), (fn), 0?(fn):(fn),              \
+                    rtype (*)(typeof(arg)))
 
 /**
  * typesafe_cb_const - cast a const callback function if it matches the arg
  *                                (arg))
  */
 #define typesafe_cb_preargs(rtype, fn, arg, ...)                       \
-       cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), (fn)+0,      \
+       cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), 0?(fn):(fn), \
                     rtype (*)(__VA_ARGS__, typeof(arg)))
 
 /**
  *                                (arg))
  */
 #define typesafe_cb_postargs(rtype, fn, arg, ...)                      \
-       cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), (fn)+0,      \
+       cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), 0?(fn):(fn), \
                     rtype (*)(typeof(arg), __VA_ARGS__))
 
 /**
  *                       typesafe_cb_cmp(int, (cmpfn), (base)), (arg))
  */
 #define typesafe_cb_cmp(rtype, cmpfn, arg)                             \
-       cast_if_type(rtype (*)(const void *, const void *), (cmpfn), (cmpfn)+0, \
+       cast_if_type(rtype (*)(const void *, const void *),             \
+                    (cmpfn), 0?(cmpfn):(cmpfn),                        \
                     rtype (*)(const typeof(*arg)*, const typeof(*arg)*))
                     
 #endif /* CCAN_CAST_IF_TYPE_H */