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[2001:8b0:bf73:93f7::51bb:e332]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46fa2cfa2dcsm23750095e9.0.2025.10.07.13.07.39 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Oct 2025 13:07:39 -0700 (PDT) Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.97) (envelope-from ) id 1v6DyD-00000000vvt-2VhL for sc22wg14@open-std.org; Tue, 07 Oct 2025 20:07:37 +0000 Date: Tue, 7 Oct 2025 20:07:37 +0000 (UTC) From: Joseph Myers To: sc22wg14@open-std.org Subject: Incomplete internal linkage tentative definitions completed in inner scope Message-ID: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: VGaPnr2B4IR4FKaqTJW5KkwRkVMT6nf2A_gRn9AVevE_1759867661 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Sender: owner-sc22wg14@open-std.org Precedence: bulk For C2y we decided to allow tentative definitions with internal linkage and incomplete type, following N3347 (accepted with a delay in Minneapolis subject to lack of objections by the end of the Graz meeting). That was accepted with wording for a new constraint taken from reflector message 26758: "If the declaration of an identifier for an object is a tentative definition with incomplete type and internal linkage, the type of the object shall be completed before the end of the translation unit.". That wording clearly improved on the originally proposed wording in the case where a second declaration completes the incomplete array type of the first declaration, but still leaves an ambiguity. Suppose the type is completed in an inner scope: static int a[]; void f() { extern int a[1]; } Is this valid, because the type gets completed in an inner scope before the end of the translation unit, or invalid, because the type at the end of the translation unit is incomplete even though the type inside f at the end of that function is complete? -- Joseph S. Myers josmyers@redhat.com