X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Futil.h;h=5147ffc5555c2e6683210af9c3b3e89b0ab0ff0a;hb=772387d560e565abf212d5863698a6834f501639;hp=9df6db5836833522dfeb955fa98e19354f232fda;hpb=a0bc29a541fc7dc6e20137d5558e2094d614e6ab;p=openvswitch

diff --git a/lib/util.h b/lib/util.h
index 9df6db58..5147ffc5 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -80,7 +80,17 @@ extern const char *program_name;
 /* Given POINTER, the address of the given MEMBER in a STRUCT object, returns
    the STRUCT object. */
 #define CONTAINER_OF(POINTER, STRUCT, MEMBER)                           \
-        ((STRUCT *) ((char *) (POINTER) - offsetof (STRUCT, MEMBER)))
+        ((STRUCT *) (void *) ((char *) (POINTER) - offsetof (STRUCT, MEMBER)))
+
+/* Given POINTER, the address of the given MEMBER within an object of the type
+ * that that OBJECT points to, returns OBJECT as a "void *" pointer.  OBJECT
+ * must be an lvalue.
+ *
+ * This is the same as CONTAINER_OF except that it infers the structure type
+ * from the type of '*OBJECT'. */
+#define OBJECT_CONTAINING(POINTER, OBJECT, MEMBER)                      \
+        ((void *) ((char *) (POINTER)                                   \
+                   - ((char *) &(OBJECT)->MEMBER - (char *) (OBJECT))))
 
 #ifdef  __cplusplus
 extern "C" {
@@ -88,7 +98,7 @@ extern "C" {
 
 void set_program_name(const char *);
 
-void ovs_print_version(char *date, char *time, 
+void ovs_print_version(char *date, char *time,
                        uint8_t min_ofp, uint8_t max_ofp);
 #define OVS_PRINT_VERSION(min_ofp, max_ofp) \
         ovs_print_version(__DATE__, __TIME__, (min_ofp), (max_ofp))