sys/cdefs.h: Introduce __maybe_unused attribute

The __maybe_unused attribute should be used for variables which may or
may not be used, such as when their only use is in an assertion. This
attribute is functionally identical to __unused, suppressing compiler
warnings for particular variable if it remains unused.

Reviewed by:	Minsoo Choo <minsoo@minsoo.io>, imp
Differential Revision:	https://reviews.freebsd.org/D56517

This commit is contained in:

Hans Rosenfeld

2026-04-16 20:22:44 +02:00

committed by

Ed Maste

parent 103f9883d1

commit 84a9574180

3 changed files with 5 additions and 3 deletions

									
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				@@ -3,7 +3,7 @@

				.\"

				.\" SPDX-License-Identifier: BSD-2-Clause

				.\"

				.Dd May 9, 2025

				.Dd May 6, 2026

				.Dt CDEFS 9

				.Os

				.Sh NAME

				@@ -85,7 +85,9 @@ linkage.

				.It Sy __weak_symbol Ta Declare the symbol to be a weak symbol

				.It Sy __dead2 Ta Function will not return

				.It Sy __pure2 Ta Function has no side effects

				.It Sy __unused Ta To Variable may be unused (usually arguments), so do not

				.It Sy __unused Ta Variable may be unused (usually arguments), so do not

				warn about it

				.It Sy __maybe_unused Ta Variable may be unused (usually arguments), so do not

				warn about it

				.It Sy __used Ta Function really is used, so emit it even if it appears unused.

				.It Sy __deprecated Ta Function interface has been deprecated, and clients