From: Jonathan Wakely <jwakely@redhat.com>
To: gcc@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Deprecating arithmetic on std::atomic<void*>
Date: Wed, 19 Apr 2017 17:07:00 -0000 [thread overview]
Message-ID: <20170419170736.GY3412@redhat.com> (raw)
I know it's a bit late, but I'd like to propose deprecating the
libstdc++ extension that allows arithmetic on std::atomic<void*>.
Currently we make it behave like arithmetic on void*, which is also a
GNU extension (https://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html).
We also allow arithmetic on types such as std::atomic<void(*)()> which
is probably not useful (PR 69769).
C++11 and C++14 were silent on the matter, but C++17 makes it
explicitly ill-formed (see https://wg21.link/p0558r1 page 2). I'm
implementing that for C++17 mode but would like it to be ill-formed
for all modes in a future release.
So I'd like to apply this patch to the gcc-7/changes.html page:
--- htdocs/gcc-7/changes.html 17 Apr 2017 22:12:35 -0000 1.77
+++ htdocs/gcc-7/changes.html 19 Apr 2017 17:05:27 -0000
@@ -38,6 +38,10 @@
</li>
<li>The Cilk+ extensions to the C and C++ languages have been deprecated.</li>
+
+ <li>The extension allowing arithmetic on <code>std::atomic<void*></code>
+ and types like <code>std::atomic<R(*)()></code>
+ has been deprecated.</li>
</ul>
<!-- .................................................................. -->
Does this seem reasonable, or do people think we need to keep this
feature, to match the core language extensions?
next reply other threads:[~2017-04-19 17:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 17:07 Jonathan Wakely [this message]
2017-04-19 17:43 ` Ville Voutilainen
2017-04-20 6:19 ` Florian Weimer
2017-04-20 9:18 ` Jonathan Wakely
2017-04-20 9:21 ` Jakub Jelinek
2017-04-20 9:25 ` Jonathan Wakely
2017-04-20 9:30 ` Jakub Jelinek
2017-04-20 9:30 ` Jonathan Wakely
2017-04-20 9:43 ` Florian Weimer
2017-04-20 9:52 ` Jonathan Wakely
2017-04-20 9:57 ` Florian Weimer
2017-04-20 10:03 ` Jonathan Wakely
2017-04-20 10:07 ` Jakub Jelinek
2017-04-20 10:12 ` Jonathan Wakely
2017-04-20 11:20 ` Jonathan Wakely
2017-04-20 12:20 ` Jonathan Wakely
2017-04-20 9:22 ` Jonathan Wakely
2017-04-20 9:25 ` Florian Weimer
2017-04-20 9:31 ` Jonathan Wakely
2017-04-20 9:39 ` Jonathan Wakely
2017-04-20 9:49 ` Florian Weimer
2017-04-20 9:53 ` Jonathan Wakely
2017-04-20 11:29 ` Pedro Alves
2017-04-20 9:31 ` Marc Glisse
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