From a88e1d1c598e641eecd5d43730211d91c82787c6 Mon Sep 17 00:00:00 2001
From: Janne Grunau <janne-libav@jannau.net>
Date: Wed, 23 Apr 2014 12:19:59 +0200
Subject: lavu: add CHK_OFFS as AV_CHECK_OFFSET to check struct member offsets

---
 libavutil/internal.h | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'libavutil/internal.h')

diff --git a/libavutil/internal.h b/libavutil/internal.h
index ecd535b808..210c52437e 100644
--- a/libavutil/internal.h
+++ b/libavutil/internal.h
@@ -84,6 +84,13 @@
 // to be forced to tokenize __VA_ARGS__
 #define E1(x) x
 
+/* Check if the hard coded offset of a struct member still matches reality.
+ * Induce a compilation failure if not.
+ */
+#define AV_CHECK_OFFSET(s, m, o) struct check_##o {    \
+        int x_##o[offsetof(s, m) == o? 1: -1];         \
+    }
+
 #define LOCAL_ALIGNED_A(a, t, v, s, o, ...)             \
     uint8_t la_##v[sizeof(t s o) + (a)];                \
     t (*v) o = (void *)FFALIGN((uintptr_t)la_##v, a)
-- 
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