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[2001:8b0:bf73:93f7::51bb:e332]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796abe3b3sm34746291f8f.18.2026.02.16.12.58.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Feb 2026 12:58:40 -0800 (PST) Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.98.2) (envelope-from ) id 1vs5fz-00000002bzD-3eou; Mon, 16 Feb 2026 20:58:39 +0000 Date: Mon, 16 Feb 2026 20:58:39 +0000 (UTC) From: Joseph Myers To: Alejandro Colomar cc: Christopher Bazley , Alex Celeste , sc22wg14 Subject: Re: [SC22WG14.35384] alx-0088r0 - noreturn can't return In-Reply-To: <20260214220545.7A903356A4E@www.open-std.org> Message-ID: References: <20260213083437.30B0A356D32@www.open-std.org> <20260214220545.7A903356A4E@www.open-std.org> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: c3JPBpDrDsWXh3IhYvVD11SNSj3JYCVwjLqWj1laD-Q_1771275521 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Sender: owner-sc22wg14@open-std.org Precedence: bulk On Sat, 14 Feb 2026, Alejandro Colomar wrote: > 6.7.5 Function specifiers > @@ Constraints, p5+1 > +A function declared with a _Noreturn function specifier > +shall not contain a return statement. What does "declared with" mean here? It can't include a declaration in another translation unit. What if the declaration with _Noreturn comes after the definition, or inside it, or is not in scope at the time of the definition because it was inside another function? This is less of an issue with the noreturn attribute because of the rules "The first declaration of a function shall specify the noreturn attribute if any declaration of that function specifies the noreturn attribute. If a function is declared with the noreturn attribute in one translation unit and the same function is declared without the noreturn attribute in another translation unit, the behavior is undefined." (though those are all in Semantics, not Constraints, and don't actually make it entirely clear which cases would be covered by your proposed constraint on the attribute). What isn't covered in the existing attribute wording is the case where the "first" declaration is inside a function and there are subsequent declarations or definition in the same translation unit without the attribute and without the prior declaration with the attribute being visible, and likewise when the prior declaration is shadowed when the function is redeclared without the attribute in block scope (but this last one is only relevant for declarations that aren't definitions). Maybe this is a defect in the existing wording about that attribute. -- Joseph S. Myers josmyers@redhat.com