[dpdk-dev] [PATCH v1 08/15] eal: define macro container_of

Jan Viktorin viktorin at rehivetech.com
Fri Jul 8 21:09:38 CEST 2016


Signed-off-by: Jan Viktorin <viktorin at rehivetech.com>
---
 lib/librte_eal/common/include/rte_common.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 332f2a4..a9b6792 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -322,6 +322,22 @@ rte_bsf32(uint32_t v)
 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
 #endif
 
+/**
+ * Return pointer to the wrapping struct instance.
+ * Example:
+ *
+ *  struct wrapper {
+ *      ...
+ *      struct child c;
+ *      ...
+ *  };
+ *
+ *  struct child *x = obtain(...);
+ *  struct wrapper *w = container_of(x, struct wrapper, c);
+ */
+#define container_of(p, type, member) \
+	((type *) (((char *) (p)) - offsetof(type, member)))
+
 #define _RTE_STR(x) #x
 /** Take a macro value and get a string version of it */
 #define RTE_STR(x) _RTE_STR(x)
-- 
2.9.0



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