This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH] PR libstdc++/80624 satisfy invariant for char_traits<char16_t>::eof()
- From: "Florian Weimer via gcc-patches" <gcc-patches at gcc dot gnu dot org>
- To: Jonathan Wakely <jwakely at redhat dot com>, libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Mon, 8 May 2017 11:53:56 +0200
- Subject: Re: [PATCH] PR libstdc++/80624 satisfy invariant for char_traits<char16_t>::eof()
- Authentication-results: sourceware.org; auth=none
- Authentication-results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com
- Authentication-results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=fweimer at redhat dot com
- Dkim-filter: OpenDKIM Filter v2.11.0 mx1.redhat.com BF76FCA1CC
- Dmarc-filter: OpenDMARC Filter v1.3.2 mx1.redhat.com BF76FCA1CC
- References: <20170505170552.GD5109@redhat.com>
- Reply-to: Florian Weimer <fweimer at redhat dot com>
On 05/05/2017 07:05 PM, Jonathan Wakely wrote:
As discussed at http://stackoverflow.com/q/43769773/981959 (and kinda
hinted at by http://wg21.link/lwg1200) there's a problem with
char_traits<char16_t>::eof() because it returns int_type(-1) which is
the same value as u'\uFFFF', a valid UTF-16 code point.
I think the real bug is that char_traits<char16_t>::int_type is just
plain wrong. It has to be a signed integer, and capable of representing
values in the range 0 .. 65535. char_traits<char32_t> has a similar
problem. char_traits<wchar_t> should be fine on glibc because WEOF is
reserved, something that is probably not the case for char32_t.
Thanks,
Florian