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Explore the rapid changes and enhancements in C++ 2011 standards process, including syntax, language features, library updates, and improved thread safety. Learn how language concepts like modules, reflection, and garbage collection were embraced, while certain features were removed. Dive into the expanded library with new algorithms, enhancements, and improved interoperability. Discover the focus on ease of use, expressiveness, and efficiency within the evolving C++ landscape, and ensure thread safety in your programming.
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Standards Process • Work under auspices of ISO SC22 WG21 • Typically 5-10 national bodies present at any meeting • More participants online • Meet 2-3 times a year for week-long meetings • Typical attendance in 50-100 range • 4 active working groups • Core • Library • Evolution • Concurrency • Work continues online at a slower pace
What was missed? • Concepts • Modules • Reflection • Full-featured Garbage Collection • “No New libraries (beyond TR1)” • TR1 math libraries • Becomes its own standard instead
What was removed • export • auto to declare local variables • access declarations • Conversion from string literal to ‘char *’ • Converts only to ‘char const *’ now • Reference counted strings
Embrace Standards • C99 + TC1 + TC2 + Unicode TR • Unicode • ECMAscript regular expressions • Posix • error handling • threads
Correctness: • explicit override ‘keyword’ • nullptr • strong enum • forwarding constructors ('strong' typedef) • static_assert • explicit conversion functions • conditionally supported behavior -> more diagnosable errors • deleted functions • detect array-new overflow • detect narrowing conversions (with new syntax) • noexcept destructors
Expressiveness: • New data types • long long • char16_t • char32_t • extended integral types • decltype • auto function declarations • extended friends • extern template • variadic templates • variadic macros • _Pragma • move semantics • perfect forwarding • defaulted functions • user defined literals • initializer lists • attributes • trivial types • fixed-base for enums • forward declare enums • enum class
Miscellaneous • inline namespaces • exception cloning • native support for type traits • __func__ and updated assert macro • implicit move constructor • implicit move-assignment operator • reference qualifiers • anonymous namespace has internal linkage • concatenate string literals of different type
Library: -------- • Almost doubled in size (by page count) • Huge effort to clean up specification • Simplify through use of common definitions • More precise contracts, using those terms • Learned a lot from the ‘concept’ experiments • Resolved roughly 6x as many issues as TC1 • (although many came from new features as library evolved!)
Adopt Language Features: • rvalue references • variadic templates • sequence constructors • constexpr • long long and extended integral types • Unicode character types • explicit bool conversion operators • deleted copy semantics • noexcept • nullptr
Support Language Features: • exception cloning • initializer lists • range-based for loop • garbage collection
TR1: • shared_ptr • binders • function • array • unordered (hashing) containers • tuple • random numbers • regular expressions • type traits • Adopt C99 library
New features: • unique_ptr and move_iterator • forward_list • atomic primitives • thread launching • thread synchronization • futures and asynch • time interval support • compile-time ratio arithmetic • clocks • portable handling of system errors • nested_exception • type_index
New Algorithms • all_of/any_of/none_of • find_if_not • copy_n/copy_if • move / move_backward • partition_copy • is_partitioned/partition_point • is_sorted/is_sorted_until • is_heap/is_heap_until • next/prev • iota • minmax / minmax_element • variadic min/max/minmax • uninitialized_copy_n
Enhancements: • emplace • cbegin/cend • consistent const_iterator to locate elements • consistent overload on std::string as well as const char * • thread-safe strings (no reference counting) • simple numeric string / std::string conversions • code conversion for wide/narrow strings • new facets : time and money • better floating point support (iostream flags / num limits) • allocator upgrade
TR1 Enhancements: • move semantics • random numbers • allocator for shared_ptr/function • shared_ptr aliasing • shared_ptr factories • atomic shared_ptr interface • more type traits : decay/conditional/enable_if • alignment calculators (type traits) • tuple concatenation • equality comparison of hashing containers
Thread Safety • basic thread-safe guarantee through library • Can safely use any library object from a single thread without locking • Sharing an object between threads requires user to synchronize access • Read-only access generally safe without locking, but a single write means reads must synchronize too! • basic_string cannot be copy-on-write • shared_ptr must have thread-safe reference counting • thread-safe access to handler functions, e.g. at_exit
Clean-up • hidden header dependencies • swap now in <utility> rather than <algorithm> • C/C++ std header implementations • allocators • vector< bool > • bitset constructors • ios_base::failure derives from system_error
Deprecated: • auto_ptr • old function binders • unary/binary_function
Where can we get it? • Most modern compilers implement a subset • static_assert • auto • decltype • rvalue references • lambda • gcc 4.6 has widest support • Clang getting good coverage if you want to build your own
