c++0x.markdown

Target Compilers

• GCC 4.4.3
  • https://gcc.gnu.org/gcc-4.4/cxx0x_status.html
• Clang 3.1
  • http://clang.llvm.org/cxx_status.html
• Intel C++ Compiler 14.0
  • https://software.intel.com/en-us/articles/c0x-features-supported-by-intel-c-compiler
• PGI Compiler 2015

Available Features in C++11

Language

• auto, decltype
  • Most of compilers do support these
• Initializer lists
  • Be careful to use
  • Bugs in GCC 4.x
    • https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55922
    • https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53361#c6
• Variadic templates
  • Be careful to use
  • Bugs in GCC 4.x
    • https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45236
    • https://gcc.gnu.org/ml/gcc-bugs/2011-05/msg01489.html
• rvalue references
  • std::move was not supported in GCC 4.3
• extern template
• Defaulted and deleted functions
  • Move constructors/assignments cannot be defaulted in GCC 4.4
• Strongly-typed enums

ICE in GCC 4.4

• decltype
  • https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47289

template <typename T>
T r(T x) { return x; }

template <typename F, typename... T>
inline auto f(F&& f, T&&... x) -> decltype(r(f)(x...)) { return f(x...); }

int g(int);

decltype(f(&g, 123)) x;

Bug in GCC

• using
  • Fixed in GCC 4.7

template <typename D>
struct A { typedef int x; };

template <typename D>
struct B : A<B<D>> {
    using typename A<B<D>>::x;
    x f() { return 1; }
};

Library

• <type_traits>

Unavailable Language Features in C++11

Language

• Template aliases
• Inheriting constructors
• Delegating constructors
• nullptr
  • Emulated by MGBASE_NULLPTR
• Alignment support
  • Use MGBASE_ALIGNOF
• Explicit virtual overrides
  • Use MGBASE_OVERRIDE
• Template arguments with internal linkage
  • DR 1155
  • Do not use locally-defined classes as template parameters

Library

Coding Rules

• Uniform initialization syntax
  • Zero argument
    • Always use {}
  • One reference
    • Use () for the old versions of GCC
  • One argument, not reference
    • Use () if we expect normal constructors
    • Use {} if we expect initializer_list<>
  • Multiple arguments
    • Use () if we expect normal constructors
    • Use {} if we expect initializer_list<>
  • Omitting return type
    • Use if the constructed type is aggregate