# C++98 and C++11 Support in Clang

Last updated: $Date$

## C++98 implementation status

Clang currently implements all of the ISO C++ 1998 standard (including the defects addressed in the ISO C++ 2003 standard) except for 'export' (which has been removed in C++11) and is considered a production-quality C++ compiler. The LLVM bug tracker contains a Clang C++ component that tracks known Clang C++ bugs.

## C++11 implementation status

Clang provides support for a number of features included in the new ISO C++ Standard, ISO/IEC 14882:2011. The following table describes which C++11 features have been implemented in Clang and in which Clang versions they became available.

By default, Clang builds C++ code according to the C++98 standard, with many C++11 features accepted as extensions. You can use Clang in C++11 mode with the `-std=c++11` option. Clang's C++11 mode can be used with libc++ or with gcc's libstdc++, but patches are needed to make libstdc++-4.4 work with Clang in C++11 mode. Patches are also needed to make libstdc++-4.6, and libstdc++-4.7 work with Clang releases prior to version 3.2 in C++11 mode.

Language Feature | C++11 Proposal | Available in Clang?
--- | --- | ---
Rvalue references | N2118 | Clang 2.9
Rvalue references for `*this` | N2439 | Clang 2.9
Initialization of class objects by rvalues | N1610 | Clang 2.9
Non-static data member initializers | N2756 | Clang 3.0
Variadic templates | N2242 | Clang 2.9
Extending variadic template template parameters | N2555 | Clang 2.9
Initializer lists | N2672 | Clang 3.1
Static assertions | N1720 | Clang 2.9
`auto`-typed variables | N1984 | Clang 2.9
Multi-declarator `auto` | N1737 | Clang 2.9
Removal of auto as a storage-class specifier | N2546 | Clang 2.9
New function declarator syntax | N2541 | Clang 2.9
Lambda expressions | N2927 | Clang 3.1
Declared type of an expression | N2343 | Clang 2.9
Incomplete return types | N3276 | Clang 3.1
Right angle brackets | N1757 | Clang 2.9
Default template arguments for function templates | DR226 | Clang 2.9
Solving the SFINAE problem for expressions | DR339 | Clang 2.9
Alias templates | N2258 | Clang 3.0
Extern templates | N1987 | Clang 2.9
Null pointer constant | N2431 | Clang 3.0
Strongly-typed enums | N2347 | Clang 2.9
Forward declarations for enums | N2764 DR1206 | Clang 3.1
Generalized attributes | N2761 | SVN (1)
Generalized constant expressions | N2235 | Clang 3.1
Alignment support | N2341 | SVN
Delegating constructors | N1986 | Clang 3.0
Inheriting constructors | N2540 | No
Explicit conversion operators | N2437 | Clang 3.0
New character types | N2249 | Clang 2.9
Unicode string literals | N2442 | Clang 3.0
Raw string literals | N2442 | Clang 3.0
Universal character names in literals | N2170 | Clang 3.1
User-defined literals | N2765 | Clang 3.1
Standard Layout Types | N2342 | Clang 3.0
Defaulted functions | N2346 | Clang 3.0
Deleted functions | N2346 | Clang 2.9
Extended friend declarations | N1791 | Clang 2.9
Extending `sizeof` | N2253 DR850 | Clang 3.1
Inline namespaces | N2535 | Clang 2.9
Unrestricted unions | N2544 | Clang 3.1
Local and unnamed types as template arguments | N2657 | Clang 2.9
Range-based for | N2930 | Clang 3.0
Explicit virtual overrides | N2928 N3206 N3272 | Clang 3.0
Minimal support for garbage collection and reachability-based leak detection | N2670 | N/A
Allowing move constructors to throw [noexcept] | N3050 | Clang 3.0
Defining move special member functions | N3053 | Clang 3.0
Concurrency
Sequence points | N2239 | SVN
Atomic operations | N2427 | Clang 3.1
Strong Compare and Exchange | N2748 | Clang 3.1 (2)
Bidirectional Fences | N2752 | Clang 3.1
Memory model | N2429 | Clang 3.2
Data-dependency ordering: atomics and memory model | N2664 | Clang 3.2 (3)
Propagating exceptions | N2179 | Clang 2.9
Abandoning a process and at_quick_exit | N2440 | N/A
Allow atomics use in signal handlers | N2547 | Clang 3.1
Thread-local storage | N2659 | No
Dynamic initialization and destruction with concurrency | N2660 | Clang 2.9
C99 Features in C++11
`__func__` predefined identifier | N2340 | Clang 2.9
C99 preprocessor | N1653 | Clang 2.9
`long long` | N1811 | Clang 2.9
Extended integral types | N1988 | N/A (4)

(1): The `[[carries_dependency]]` attribute has no effect.
(2): All compare-exchange operations are emitted as strong compare-exchanges.
(3): `memory_order_consume` is lowered to `memory_order_acquire`.
(4): `__int128` is not treated as an extended integer type, because changing `intmax_t` would be an ABI-incompatible change.