From: Maria Matejka <mq@ucw.cz>
Date: Wed, 13 Oct 2021 09:33:48 +0000 (+0200)
Subject: Type checking in SKIP_BACK macro
X-Git-Tag: 3.0-alpha0~92
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d7e42cc593b3c99f8eacaaa506194aeb3a5cf85;p=thirdparty%2Fbird.git

Type checking in SKIP_BACK macro
---

diff --git a/lib/birdlib.h b/lib/birdlib.h
index 431b7c0d8..2e642d384 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -16,7 +16,7 @@
 struct align_probe { char x; long int y; };
 
 #define OFFSETOF(s, i) ((size_t) &((s *)0)->i)
-#define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i)))
+#define SKIP_BACK(s, i, p) ({ s *_ptr = ((s *)((char *)p - OFFSETOF(s, i))); ASSERT_DIE(&_ptr->i == p); _ptr; })
 #define BIRD_ALIGN(s, a) (((s)+a-1)&~(a-1))
 #define CPU_STRUCT_ALIGN (sizeof(struct align_probe))