public inbox for
help / color / mirror / Atom feed
* gcc-wwwdocs branch master updated. 2feaab534eb731bfc91f41b9e6f4afe9f6898828
@ 2020-09-15  1:09 Marek Polacek
  0 siblings, 0 replies; only message in thread
From: Marek Polacek @ 2020-09-15  1:09 UTC (permalink / raw)
  To: gcc-cvs-wwwdocs

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "gcc-wwwdocs".

The branch, master has been updated
       via  2feaab534eb731bfc91f41b9e6f4afe9f6898828 (commit)
      from  2a1071ff337f3c060c12d3d4c65cd39cf3b01954 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
commit 2feaab534eb731bfc91f41b9e6f4afe9f6898828
Author: Marek Polacek <>
Date:   Mon Sep 14 21:08:09 2020 -0400

    Add porting_to for GCC 11.

diff --git a/htdocs/gcc-11/porting_to.html b/htdocs/gcc-11/porting_to.html
new file mode 100644
index 00000000..e51285d9
--- /dev/null
+++ b/htdocs/gcc-11/porting_to.html
@@ -0,0 +1,82 @@
+<!DOCTYPE html>
+<html lang="en">
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+<title>Porting to GCC 11</title>
+<link rel="stylesheet" type="text/css" href="" />
+<h1>Porting to GCC 11</h1>
+The GCC 11 release series differs from previous GCC releases in
+<a href="changes.html">a number of ways</a>. Some of these are a result
+of bug fixing, and some old behaviors have been intentionally changed
+to support new standards, or relaxed in standards-conforming ways to
+facilitate compilation or run-time performance.
+Some of these changes are user visible and can cause grief when
+porting to GCC 11. This document is an effort to identify common issues
+and provide solutions. Let us know if you have suggestions for improvements!
+<h2 id="cpp">Preprocessor issues</h2>
+<h2 id="c">C language issues</h2>
+<h2 id="cxx">C++ language issues</h2>
+<h3 id="gxx17">Default standard is now GNU++17</h3>
+GCC 11 defaults to <code>-std=gnu++17</code> instead of <code>-std=gnu++14</code>:
+the C++17 standard, plus GNU extensions.
+This brings several changes that users should be aware of.  The following
+paragraphs describe some of these changes and suggest how to deal with them.
+<p>Some users might prefer to stay with gnu++14, in which case we suggest to
+use the <code>-std=gnu++14</code> command-line option, perhaps by putting it
+in <code>CXXFLAGS</code> or similar variables in Makefiles.</p>
+<h3 id="template-template-changes">Template template parameter matching changes</h3>
+G++, starting with
+<a href=";a=commit;h=31bfc9b9">G++ 7</a>,
+implements C++17
+<a href="">P0522R0</a>,
+Matching of template template-arguments excludes compatible templates.  As a
+consequence, the following test is now rejected:
+    template &lt;int N, int M = N&gt; class A;
+    template &lt;int N, int M&gt; void fn(A&lt;N, M&gt; &amp;) {}
+    template &lt;int N, template &lt;int&gt; class TT&gt; void fn(TT&lt;N&gt; &amp;);
+    template void fn(A&lt;3&gt; &amp;);
+because <code>A</code> is now considered a valid argument for <code>TT</code>,
+so both function templates are valid candidates, and neither is more specialized
+than the other, so it's ambiguous.
+The new behavior can be disabled independently of other C++17 features with
+<h2 id="fortran">Fortran language issues</h2>
+<h2 id="links">Links</h2>


Summary of changes:
 htdocs/gcc-11/porting_to.html | 82 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 htdocs/gcc-11/porting_to.html


^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2020-09-15  1:09 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-15  1:09 gcc-wwwdocs branch master updated. 2feaab534eb731bfc91f41b9e6f4afe9f6898828 Marek Polacek

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).