From 8372b50a6faa2883a6bd15fde121fcb47e6d43e9 Mon Sep 17 00:00:00 2001
From: dybucc <149513579+dybucc@users.noreply.github.com>
Date: Thu, 18 Jun 2026 15:53:52 +0200
Subject: [PATCH] feat: add macro to declare unstable constants

This patch adds a new macro that can be used for declaring constants
when these are known to possibly change upstream across target OS/ABI
versions.
---
 src/macros.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/macros.rs b/src/macros.rs
index 0149b1fd18466..5c5b8c2deac79 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -402,6 +402,21 @@ macro_rules! offset_of {
     }};
 }
 
+/// Defines constants with an accompanying doc comment pointing out their
+/// instability, and links to the crate documentation for usage guidelines.
+macro_rules! ct {
+    ($($it:item)+) => {
+$(
+/// This constant, among others often used in C for the purposes of denoting the
+/// latest value or limit in a set of constants, is likely to change upstream.
+/// For correct usage, see the [crate-level documentation][docs].
+///
+/// [docs]: index.html#usage-recommendations
+$it
+)+
+    };
+}
+
 #[cfg(test)]
 mod tests {
     use core::any::TypeId;