From ec95c3c5f795ce9019809fec5578fabb22ec8c56 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Wed, 9 Jun 2021 15:12:28 +0930
Subject: [PATCH] compiler: RETURNS_NONNULL macro

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 ccan/compiler/compiler.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/ccan/compiler/compiler.h b/ccan/compiler/compiler.h
index 1bbb3b8b..562b29ec 100644
--- a/ccan/compiler/compiler.h
+++ b/ccan/compiler/compiler.h
@@ -271,6 +271,19 @@
 #define NON_NULL_ARGS(...)
 #endif
 
+#if HAVE_ATTRIBUTE_RETURNS_NONNULL
+/**
+ * RETURNS_NONNULL - specify that this function cannot return NULL.
+ *
+ * Mainly an optimization opportunity, but can also suppress warnings.
+ *
+ * Example:
+ * RETURNS_NONNULL char *my_copy(char *buf);
+ */
+#define RETURNS_NONNULL __attribute__((__returns_nonnull__))
+#else
+#define RETURNS_NONNULL
+#endif
 
 #if HAVE_ATTRIBUTE_SENTINEL
 /**
-- 
2.39.2