From owner-sc22wg14+sc22wg14-domo2=www.open-std.org@open-std.org Tue Aug 25 19:46:57 2026 Return-Path: X-Original-To: sc22wg14-domo2 Delivered-To: sc22wg14-domo2@www.open-std.org Received: by www.open-std.org (Postfix, from userid 521) id DCD6C356E57; Tue, 25 Aug 2026 19:46:57 +0200 (CEST) Delivered-To: sc22wg14@open-std.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by www.open-std.org (Postfix) with ESMTP id 5D109356E40 for ; Tue, 25 Aug 2026 19:46:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787680016; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type; bh=BvVco+AXJ5u3SGufkJbyZeAlCJKPEHwsAt9HVMObGuw=; b=hyl3F7jFzefc8qI5fOEJCKyRM9wlRPBtxCSCeUHqIPUB97qxivhVvuUGM8Qhh1iJs8lqDP 7WZAqrVFUECUWI+qSt91YzPLIck12QFGGN3pC6pdddjGwowXRfVN82vLlgPisA5itjKOUc ULZQuy4b1+EuXtsbX1DYdDp7RQM7pqg= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-628-MkR9utDTNEKMWJRGtdojlg-1; Tue, 25 Aug 2026 13:46:54 -0400 X-MC-Unique: MkR9utDTNEKMWJRGtdojlg-1 X-Mimecast-MFC-AGG-ID: MkR9utDTNEKMWJRGtdojlg_1787680013 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-499cfd815f8so18872235e9.3 for ; Tue, 25 Aug 2026 10:46:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787680013; x=1788284813; h=content-type:mime-version:message-id:subject:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=BvVco+AXJ5u3SGufkJbyZeAlCJKPEHwsAt9HVMObGuw=; b=syt7nSjmFr9geKBhzjZ1m/83+Mls3sTtlBsY/dmcxyboZp7TuJP7R7ueeYBbyJKllT WOk7QDIZjiTZoiT6otd7WKKOvmkPOZmOhgDeCNXSSbM2JddbLsOgnuMY0RvBccNaxnVl /FlUf4XGzOQ4eel3n04OffyEGDBAhKJMsR+juxWi+aEjbLhBxhC9Ka1lQQbKqmByycBR b+sFW2tE2y26m6qLao094PzGnETd6aV/yPAI8OC9HV4VZQ3HbLIH1BfgtyEejqykgWeD qhXieipOYT5btOFJYO3vDRs7QU+WPucy7r7fqBX9qQ3wsKmpHtYcmgOe+x0WHnaR/fhZ jtZQ== X-Gm-Message-State: AFuF++kY+7iPHx+g13UvEPppAQnHgro3Dug6GNkhqZVHyat4NIdr6O4W mgWpL6RTfOo90CTg3cnqWcqS/8Iw7uNZuSzGjOJOQF5a6B6FiUdMMBnsFntCgJVPNJVgZRPrWB9 GoZMTm6VMxLqwQO8ZmIx5qp5krBpGxTsxQpdwy8eg3L0k6GZezCHLV6mpiRjyx0rXC0AJpco2F3 Aque7AUUTIVZn2HErargtdzGt/WsICJlt17AjVPHyT X-Gm-Gg: AR+sD103T0k+NVwjafnnIpTjKIXDwFDuvuHzI5MeWGCRN04LHPW95QfFiYgwKQwkMnk yBrC/Loz/2/hb1d6M7lhi0pSpVYf3AsZdEeSrTYl8F5ZI2TzOHmok1Xrznvb8evLtlkdMPGzTKt UoBXUYzgNm7njskB+Lkuwl9yd78gVSJm9mzbgE95g/q6fviE6D8FsgjdNZ6+C1+uvIedwewQci2 PYKMWfmszmTQjIgQjFevFlCdeNQ25nkGsasWRAs11aj6eGM3hIst0uzh21JzEEPBzs9FjIa1q3u wY/Sx1qq8+9Z+kYFrOO7OArO+RQgXxn2rPUKWPeHKXDP6N3HkVC3+sFnDaOYJJFjw4ZmpKdQDdT BzXF3SSMSxWl3mKt7oDlfcB0yxTRT0rE= X-Received: by 2002:a05:600c:1e0a:b0:496:c18c:f9a3 with SMTP id 5b1f17b1804b1-499dc6eddf5mr8932665e9.5.1787680012999; Tue, 25 Aug 2026 10:46:52 -0700 (PDT) X-Received: by 2002:a05:600c:1e0a:b0:496:c18c:f9a3 with SMTP id 5b1f17b1804b1-499dc6eddf5mr8932125e9.5.1787680012489; Tue, 25 Aug 2026 10:46:52 -0700 (PDT) Received: from digraph.polyomino.org.uk (digraph.polyomino.org.uk. [2001:8b0:bf73:93f7::51bb:e332]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499dca97883sm687405e9.6.2026.08.25.10.46.51 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Aug 2026 10:46:52 -0700 (PDT) Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.98.2) (envelope-from ) id 1wyvEZ-00000006YHg-1Obz for sc22wg14@open-std.org; Tue, 25 Aug 2026 17:46:51 +0000 Date: Tue, 25 Aug 2026 17:46:51 +0000 (UTC) From: Joseph Myers To: sc22wg14@open-std.org Subject: Which standard library types can be array types (issue 1026) Message-ID: <6a9e6876-8b59-4290-60e5-0cc8c500816e@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: e3ZJ2pQd8Pef3oHNqapEiABSEPxrkjVF8bxCLNxG25E_1787680013 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Sender: owner-sc22wg14@open-std.org Precedence: bulk In discussion of issue 1026 (thrd_t as array type) in Ottawa it was suggested that the default for standard library types should be not allowing them to be array types, rather than excluding array types in particular places. fpos_t and mbstate_t are explicitly excluded from being array types at present. jmp_buf is required to be an array type. We know that va_list needs to be permitted (but not required) to be an array type. If we make the default that array types are not allowed, this would affect all of the following that don't currently say they are not array types: fenv_t femode_t fexcept_t va_list max_align_t FILE cnd_t thrd_t tss_t mtx_t once_flag the atomic integer types in 7.17.6 For va_list we'd need to add explicit permission to be an array type. For thrd_t, changing it is the point of the issue. I can't think that any of the atomic integer types in 7.17.6 is meant to be an array type, but strictly saying what representation and alignment requirements they have may not actually require them to be implemented in a way that excludes an array type. (Lots of other types are explicitly described as integer types, real types, structure types, etc., which *does* prevent them from being array types.) So should all of fenv_t femode_t fexcept_t va_list max_align_t FILE cnd_t tss_t mtx_t once_flag have wording added that says they may be array types? If not, which should be permitted to be array types and which should not? (tss_t is of particular interest here since various functions take a parameter declared as tss_t not tss_t*, so suggesting it was not anticipated to be an array type.) If most of these should be allowed to be array types, when only fpos_t, mbstate_t, thrd_t, tss_t and the atomic integer types should be excluded, maybe it isn't such a good idea after all to make the default be to exclude array types? (For the atomic integer types, maybe the right approach is to require them to be the same as the corresponding direct types rather than only having same representation and alignment.) -- Joseph S. Myers josmyers@redhat.com