DKIM-Filter: OpenDKIM Filter v2.11.0 delorie.com 49UG1KfC3313657
Authentication-Results: delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=myQNoQpl
X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 19631385843D
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1730304080;
	bh=SylBiJ98FaN2MDP0DTcVMjHweFXjbdhLlLg/zlA/uJ0=;
	h=Subject:In-Reply-To:Date:Cc:References:To:List-Id:
	 List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe:
	 From:Reply-To:From;
	b=myQNoQplq2rnV+cpRQYtKHqnpZt+kdWlO4uveq3yzZVrJm+1gZmT97Vu6AWQ3h1Z2
	 OBgtE7sPond+3Q5QPO5+fDJLLn97B4TMfyMwLh7uHcgnx3MjOBwc4zdMaLihDvK96e
	 WygnAzPOYlh7NFGuuQ+QJel40PNotFv56cjPRS/A=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 0729F3858290
ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 0729F3858290
ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1730304054; cv=none;
 b=blyn/I2QdCDFthi+DsX6F0cxKsKVv5I7grqlVOfhyccOd66fYTQX3I0o/3zYpLyOy3Lp8xlxvElIAqnd1scFUH4Nk2hWfwQSy8g2KPNKaGWd7MTM29xVvqQyQA1XR/sgoC+YAlqke7VbwXa8hnHp6dOyJ4ExsLJT8p8XcopMLiU=
ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key;
 t=1730304054; c=relaxed/simple;
 bh=rvy3uoQFI2tVtVVLgVBc0E9w9PPwD2eXqwcXiVxnsv0=;
 h=DKIM-Signature:Mime-Version:Subject:From:Date:Message-Id:To;
 b=U6OKus8lgzgsHoZHf/dN0RPlPTyatySugFWi3a8MML+v7Uetmqo/1P75psTcpNj4mAinU6g53jUl2ot+pEZ/cjPpfFarACG3iTWdmDxArj5H/2f6bYrr9jvPnoNwJJbV57CDHt0xxQZKYZDwu6ujmXiYVJ2U4sXNtBoNdGtyVWk=
ARC-Authentication-Results: i=1; server2.sourceware.org
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20230601; t=1730304046; x=1730908846;
 h=to:references:message-id:content-transfer-encoding:cc:date
 :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc
 :subject:date:message-id:reply-to;
 bh=92RRI1MEjSs1ToXhholPvnRoK2tHUynw5wWvIBCwUtM=;
 b=OYGLvtkorx/fkMzm565cIhj9U+ReSFdI/wO3SeD1DwCeHVR8ZC3BJFS/HItsCQvZQx
 eKF7ZXPwJJ2gD8bkQ94u55pHI+CzsFcP24BztyocwRliYeVG5abvXkvPn84CFkN7rcXo
 n9jidbjDz4RvR0anewQ+33u37RPa9waeUBonzNtNtX3nA4lCUteePIZXN0NPjVakJcX3
 hwpISPfAfx9hzZ4TuY6uGbiizC9w9ORPg37+fe93CXWCWhbuFAY4/ThP5i9KIgZeHJuV
 Pmkt3RYjXdOkiYWpCLSEP+w70rm9sfhO/sHYgeC8uMiiYKuwNVrWkq+u4e42lyD5YB2K
 Nt0g==
X-Gm-Message-State: AOJu0YwKrrypktut3/+2wcXC7plcpv+ZS0lsiFzX5Af8EBtxKISFRMxL
 YFL/3tkDEQp2nwLn/KjThUw3+SvqOm2j4DWDzuZkK+Gfk6xOreDaUhiyZxhZKeHIkI7zMXCG/6d
 1aCJkRp5EzHX6LSRPe5WuIHERrpJCvRZQs5e5b8IPSrO/YgaoO98gGK9s94W45teRqeTpPtIbvq
 VWaasGEZ7IQLdaTqyKcOBTuNpyOUICm3qWhh0rKZXGSKi/Cw==
X-Google-Smtp-Source: AGHT+IGFyVpmZCydnMHjL976kQvenbcWx72g3cnSB25kNTm9fBoG4D8+/LT92+RgHHgm4fTJlWYT1A==
X-Received: by 2002:a17:907:7b9e:b0:a9a:dac:2ab9 with SMTP id
 a640c23a62f3a-a9e3a6c99ebmr354775866b.42.1730304046021; 
 Wed, 30 Oct 2024 09:00:46 -0700 (PDT)
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.700.6.1.9\))
Subject: Re: g++ 12 -std=gnu++20
In-Reply-To: <48e51b50-63db-4b14-b321-46942e40862e@SystematicSW.ab.ca>
Date: Wed, 30 Oct 2024 17:00:44 +0100
Cc: Brian Inglis <Brian DOT Inglis AT SystematicSW DOT ab DOT ca>
Message-Id: <3805509C-51BA-46F9-95A3-007CE99B014A@unified-streaming.com>
References: <48e51b50-63db-4b14-b321-46942e40862e AT SystematicSW DOT ab DOT ca>
To: cygwin AT cygwin DOT com
X-Mailer: Apple Mail (2.3731.700.6.1.9)
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <https://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: Dimitry Andric via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Dimitry Andric <dimitry AT unified-streaming DOT com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

On 30 Oct 2024, at 16:06, Brian Inglis via Cygwin <cygwin AT cygwin DOT com> wrote:
> Trying to update a package using c++ (requires gcc 12.4+ for adequate c++ 2020 support) and getting confusing error messages.
> 
> It appears that noexcept in the header files may here redefined by the compiler or headers as __GLIBC_NOEXCEPT.
> Those errors look to me like a failure to detect that *glibc* is not available.
> Or is *GLIBCXX* actually *glib* for *cxx*, so this could be a library or compiler issue?
> 
> It appears that str::size() should be a constexpr but something messes it up.
> Or is something else going on here?

As far as I can determine, even a simple example does not work for gcc 12:

#include<string>
#include<cassert>

constexpr bool foo()
{
  std::string str2{"abcwe"};
  return str2.size()==5;
}

static_assert(foo());

int main()
{
  assert(foo());
}

As far as I know, there is no gcc 13 for Cygwin yet, but on Linux and FreeBSD this does compile with gcc 13.

-Dimitry


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple