From: Maria Matejka <mq@ucw.cz>
Date: Tue, 4 Feb 2025 09:41:05 +0000 (+0100)
Subject: Fixed SAME_TYPE to work with obviously nonzero pointers without warnings
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=87236d8cb6feb145fe59baee1321b36a3da89b4f;p=thirdparty%2Fbird.git

Fixed SAME_TYPE to work with obviously nonzero pointers without warnings
---

diff --git a/lib/birdlib.h b/lib/birdlib.h
index bc7c334cb..ab96f99b7 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -21,8 +21,9 @@
 
 /* Ugly structure offset handling macros */
 
+extern char invalid_nonzero_pointer[0];
 #define SAME_TYPE(a, b)	({ int _ = ((a) != (b)); !_; })
-#define TYPE_CAST(from, to, what) ( SAME_TYPE(((from) NULL), (what)), ((to) (what)))
+#define TYPE_CAST(from, to, what) ( SAME_TYPE(((from) invalid_nonzero_pointer), (what)), ((to) (what)))
 
 #ifdef offsetof
 #define OFFSETOF offsetof
diff --git a/lib/resource.c b/lib/resource.c
index 8a923792f..a389403b0 100644
--- a/lib/resource.c
+++ b/lib/resource.c
@@ -30,6 +30,8 @@
  * is freed upon shutdown of the module.
  */
 
+char invalid_nonzero_pointer[0];
+
 static void pool_dump(struct dump_request *, resource *);
 static void pool_free(resource *);
 static resource *pool_lookup(resource *, unsigned long);