From 364c6001dc827ff7b0ee3bc209ddccab36bf2a7f Mon Sep 17 00:00:00 2001
From: ridiculousfish <rf@fishshell.com>
Date: Sat, 25 Jul 2020 12:39:06 -0700
Subject: [PATCH] Introduce __warn_unused_type

This is like __warn_unused, but it says that any time this type is
returned from a function it must be used. This will help enforce error
handling.
---
 config_cmake.h.in | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/config_cmake.h.in b/config_cmake.h.in
index 35e9d764f..2a8532d2f 100644
--- a/config_cmake.h.in
+++ b/config_cmake.h.in
@@ -170,6 +170,7 @@
 /* Define to 1 if mbrtowc attempts to convert invalid UTF-8 sequences */
 #cmakedefine HAVE_BROKEN_MBRTOWC_UTF8 1
 
+/* Support __warn_unused on function return values. */
 #if __GNUC__ >= 3
 #ifndef __warn_unused
 #define __warn_unused __attribute__ ((warn_unused_result))
@@ -177,3 +178,14 @@
 #else
 #define __warn_unused
 #endif
+
+/* Like __warn_unused, but applies to a type.
+   At the moment only clang supports this as a type attribute.
+*/
+#if defined(__clang__) && __has_attribute(warn_unused_result)
+#ifndef __warn_unused_type
+#define __warn_unused_type __attribute__ ((warn_unused_result))
+#endif
+#else
+#define __warn_unused_type
+#endif