From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: [committed] libstdc++: Update documentation comments for namespace rel_ops
Date: Fri, 23 Jul 2021 11:45:24 +0100 [thread overview]
Message-ID: <YPqdxOyyws+M2RhA@redhat.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 730 bytes --]
The comments in <bits/stl_relops.h> describe problems that were solved
years ago (for GCC 3.1). The comparison operators in <iterator> are no
longer ambiguous with the rel_ops ones, so the linked mailing list
thread and FAQ entry aren't relevant now. The reference to std_utility.h
is also outdated as it's just called utility now, both in the source
tree and when installed.
The use of rel_ops is still frowned upon though, so replace the
discussion of ambiguities within libstdc++ headers with adminition about
using rel_ops in user code.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/stl_relops.h: Update documentation comments.
Tested powerpc64le-linux. Committed to trunk.
[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 2392 bytes --]
commit 5b965dc49a6a4293ce85bc3a24ca3f3855469e68
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Jul 23 11:03:23 2021
libstdc++: Update documentation comments for namespace rel_ops
The comments in <bits/stl_relops.h> describe problems that were solved
years ago (for GCC 3.1). The comparison operators in <iterator> are no
longer ambiguous with the rel_ops ones, so the linked mailing list
thread and FAQ entry aren't relevant now. The reference to std_utility.h
is also outdated as it's just called utility now, both in the source
tree and when installed.
The use of rel_ops is still frowned upon though, so replace the
discussion of ambiguities within libstdc++ headers with adminition about
using rel_ops in user code.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/stl_relops.h: Update documentation comments.
diff --git a/libstdc++-v3/include/bits/stl_relops.h b/libstdc++-v3/include/bits/stl_relops.h
index 276894c435a..ef522031318 100644
--- a/libstdc++-v3/include/bits/stl_relops.h
+++ b/libstdc++-v3/include/bits/stl_relops.h
@@ -52,13 +52,8 @@
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{utility}
*
- * Inclusion of this file has been removed from
- * all of the other STL headers for safety reasons, except std_utility.h.
- * For more information, see the thread of about twenty messages starting
- * with http://gcc.gnu.org/ml/libstdc++/2001-01/msg00223.html, or
- * http://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.ambiguous_overloads
- *
- * Short summary: the rel_ops operators should be avoided for the present.
+ * This file is only included by `<utility>`, which is required by the
+ * standard to define namespace `rel_ops` and its contents.
*/
#ifndef _STL_RELOPS_H
@@ -72,6 +67,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
/** @namespace std::rel_ops
* @brief The generated relational operators are sequestered here.
+ *
+ * Libstdc++ headers must not use the contents of `rel_ops`.
+ * User code should also avoid them, because unconstrained function
+ * templates are too greedy and can easily cause ambiguities.
+ *
+ * C++20 default comparisons are a better solution.
*/
/**
reply other threads:[~2021-07-23 10:45 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YPqdxOyyws+M2RhA@redhat.com \
--to=jwakely@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=libstdc++@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).