Clang 3.1 Release Notes
These are in-progress notes for the upcoming Clang 3.1
release.
You may prefer the
Clang 3.0
Release Notes.
Introduction
This document contains the release notes for the Clang C/C++/Objective-C frontend, part of the LLVM Compiler Infrastructure, release 3.1. Here we describe the status of Clang in some detail, including major improvements from the previous release and new feature work. For the general LLVM release notes, see the LLVM documentation. All LLVM releases may be downloaded from the LLVM releases web site.
For more information about Clang or LLVM, including information about the latest release, please check out the main please see the Clang Web Site or the LLVM Web Site.
Note that if you are reading this file from a Subversion checkout or the main Clang web page, this document applies to the next release, not the current one. To see the release notes for a specific release, please see the releases page.
What's New in Clang 3.1?
Some of the major new features and improvements to Clang are listed here. Generic improvements to Clang as a whole or two its underlying infrastructure are described first, followed by language-specific sections with improvements to Clang's support for those languages.
Major New Features
Feature 1
...New and better diagnostics
New: -Wdangling-else, -Wstrncat-size, ...
Improved: -Wformat, -Wempty-body,
-Wliteral-conversion, ...
Tooling
Added an API to enable clang-based standalone tools, including initial build system integration.
C Language Changes in Clang
C11 Feature Support
Clang 3.1 adds support for anonymous structs and anonymous unions, added in
the latest ISO C standard. Use -std=c11 or -std=gnu11
to enable support for the new language standard. The new C11 features are
backwards-compatible and are available as an extension in all language
modes.
All warning and language selection flags which previously accepted
c1x have been updated to accept c11. The old
c1x forms have been removed.
C++ Language Changes in Clang
C++11 Feature Support
Clang 3.1 adds support for
more of the language
features added in the latest ISO C++ standard,
C++ 2011.
Use -std=c++11 or -std=gnu++11 to enable support for
these features. In addition to the features supported by Clang 3.0, the
following are now considered to be of production quality:
- Generalized constant expressions
- Lambda expressions
- Generalized initializers
- Unrestricted unions
- User-defined literals
- Forward-declared enumerations
- Atomics (both libc++'s and libstdc++4.7's <atomic> are supported)
Objective-C Language Changes in Clang
Clang 3.1 introduces several new Objective-C language features and improvements.Format string checking for NSString literals
-Wformat now checks @"nsstring literals".
Internal API Changes
These are major API changes that have happened since the 3.0 release of Clang. If upgrading an external codebase that uses Clang as a library, this section should help get you past the largest hurdles of upgrading.API change 1
...Significant Known Problems
Additional Information
A wide variety of additional information is available on the Clang web page. The web page contains versions of the API documentation which are up-to-date with the Subversion version of the source code. You can access versions of these documents specific to this release by going into the "clang/doc/" directory in the Clang tree.
If you have any questions or comments about Clang, please feel free to contact us via the mailing list.