Hi!
This mentions -Wunused-but-set-* warnings (which are C/C++/ObjC/ObjC++, so
not sure how to mention them in the language specific areas instead) and
briefly mentions removal of <cstddef> includes. More should go probably
into gcc-4.6/porting_to.html.
--- htdocs/gcc-4.6/changes.html.jj 2011-03-10 16:32:07.000000000 +0100
+++ htdocs/gcc-4.6/changes.html 2011-03-10 16:52:07.000000000 +0100
@@ -57,6 +57,17 @@
<code>libquadmath</code> library is automatically built on
such targets when building the Fortran compiler.</li>
+ <li>New <code>-Wunused-but-set-variable</code> and
+ <code>-Wunused-but-set-parameter</code> warnings were added
+ for C, C++, Objective-C and Objective-C++.
+ These warnings diagnose variables respective parameters which
+ are only set in the code and never otherwise used.
+ Usually such variables are useless and often even the value
+ assigned to them is computed needlessly, sometimes expensively.
+ The <code>-Wunused-but-set-variable</code> warning is enabled by
+ default by <code>-Wall</code> flag and
<code>-Wunused-but-set-parameter</code>
+ by <code>-Wall -W</code> flags.</li>
+
<li><p>Support for a number of older systems and recently
unmaintained or untested target ports of GCC has been declared
obsolete in GCC 4.6. Unless there is activity to revive them, the
@@ -418,6 +429,10 @@
they can be understood by race detectors such as Helgrind, see
<a
href="http://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html#debug.races";>Data
Race Hunting</a>.</li>
+ <li>Most libstdc++ standard headers have been changed to longer include
+ <code>cstddef</code> header as an implementation detail. Code that
+ relied on that header being included as side-effect of including other
+ standard headers will need include <code>cstddef</code> explicitly.</li>
</ul>
<h3 id="fortran">Fortran</h3>
Jakub
