C++0x Support in GCC

C++0x is the working name of the next ISO C++ standard, due by the end of this decade, which introduces a host of new features into the standard C++ language and library. This project seeks to implement new C++0x features in GCC and to make it one of the first compilers to bring C++0x to C++ programmers.

C++0x features are available as part of the "mainline" GCC compiler in the trunk of GCC's Subversion repository and in GCC 4.3 and later. To enable C++0x support, add the command-line parameter -std=c++0x to your g++ command line. Or, to enable GNU extensions in addition to C++0x extensions, add -std=gnu++0x to your g++ command line.

Important: because the ISO C++0x draft is still evolving, GCC's support for C++0x is experimental. No attempt will be made to maintain backward compatibility with implementations of C++0x features that do not reflect the final C++0x standard.

C++0x Language Features

The following table lists new language features that have been accepted into the C++0x draft standard. The "Proposal" column provides a link to the ISO C++ committee proposal that describes the feature, while the "Available in GCC?" column indicates the first version of GCC that contains an implementation of this feature (if it has been implemented). For the most complete and up-to-date information about new language features in C++0x, please see the ISO C++ Committee Papers and look for the most recent "State of C++ Evolution" paper by Alisdair Meridith.

For information about C++0x support in a specific version of GCC, please see:

Language Feature Proposal Available in GCC?
Rvalue references N2118 GCC 4.3
    Rvalue references for *this N2439 No
Initialization of class objects by rvalues N1610 Yes
Non-static data member initializers N2756 No
Variadic templates N2242 GCC 4.3
    Extending variadic template template parameters N2555 GCC 4.4
Initializer lists N2672 GCC 4.4
Static assertions N1720 GCC 4.3
auto-typed variables N1984 GCC 4.4
    Multi-declarator auto N1737 GCC 4.4
    Removal of auto as a storage-class specifier N2546 GCC 4.4
    New function declarator syntax N2541 GCC 4.4
New wording for C++0x lambdas N2927 GCC 4.5
Declared type of an expression N2343 GCC 4.3
Right angle brackets N1757 GCC 4.3
Default template arguments for function templates DR226 GCC 4.3
Solving the SFINAE problem for expressions DR339 GCC 4.4
Template aliases N2258 No
Extern templates N1987 Yes
Null pointer constant N2431 GCC 4.6
Strongly-typed enums N2347 GCC 4.4
Forward declarations for enums N2764 No
Generalized attributes N2761 No
Generalized constant expressions N2235 No
[Branch]
Alignment support N2341 No
Delegating constructors N1986 No
[Patch]
Inheriting constructors N2540 No
Explicit conversion operators N2437 GCC 4.5
New character types N2249 GCC 4.4
Unicode string literals N2442 GCC 4.5
Raw string literals N2442 GCC 4.5
Universal character name literals N2170 GCC 4.5
Extensible literals N2765 No
Standard Layout Types N2342 GCC 4.5
Defaulted and deleted functions N2346 GCC 4.4
Extended friend declarations N1791 No
Extending sizeof N2253 GCC 4.4
Inline namespaces N2535 GCC 4.4
Unrestricted unions N2544 GCC 4.6
Local and unnamed types as template arguments N2657 GCC 4.5
Range-based for N2930 No
Explicit virtual overrides N2928 No
Minimal support for garbage collection and reachability-based leak detection N2670 No
Allowing move constructors to throw [noexcept] N3050 GCC 4.6 (core language only)
Defining move special member functions N3053 GCC 4.6
Concepts [no longer part of C++0x] N2773 Some development
[Branch]
Concurrency
Sequence points N2239 No
Atomic operations N2427 GCC 4.4
Strong Compare and Exchange N2748 No
Bidirectional Fences N2752 No
Memory model N2429 No
Data-dependency ordering: atomics and memory model N2664 No
Propagating exceptions N2179 GCC 4.4
Abandoning a process and at_quick_exit N2440 No
Allow atomics use in signal handlers N2547 No
Thread-local storage N2659 No
Dynamic initialization and destruction with concurrency N2660 No
C99 Features in C++0x
__func__ predefined identifier N2340 GCC 4.3
C99 preprocessor N1653 GCC 4.3
long long N1811 GCC 4.3
Extended integral types N1988 No

C++0x Library Features

The status of the library implementation can be tracked in this table

Ongoing C++0x Development

C++0x constexpr branch

Significant work has been done on the constexpr feature of C++0x. The sources can be found on the constexpr branch in the GCC git mirror. If you are interested in helping, you can send patches to the gcc-patches mailing list as usual (preferably with "c++0x constexpr" in the subject line), or send a pull request to [email protected].

C++0x Concepts Branch

Support for the Concepts feature, which is no longer part of C++0x, is not under active development at this time. The prototype implementation, ConceptGCC, can be found on the branches/conceptgcc-branch. Previously there was a plan to develop a superior implementation on a separate development branch, branches/cxx0x-concepts-branch, but not much work was done on that branch.

Please send FSF & GNU inquiries & questions to [email protected]. There are also other ways to contact the FSF.

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For questions related to the use of GCC, please consult these web pages and the GCC manuals. If that fails, the [email protected] mailing list might help.
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