C++ standard libraries extensions, version 2 (original) (raw)
Version 2 of the C++ Extensions for Library Fundamentals, ISO/IEC TS 19568:2017, defines the following new components for the C++ standard library, in addition to those defined in version 1:
Contents
- 1 The C++ detection idiom
- 2 A const-propagating wrapper for pointer-like objects
- 3 Non-owning pointers
- 4 std::array creation
- 5 ostream_joiner
- 6 Simple random number generation facilities
- 7 Feature test macros
- 8 Merged into C++17
- 9 Merged into C++20
[edit] The C++ detection idiom
[edit] A const-propagating wrapper for pointer-like objects
[edit] Non-owning pointers
[edit] std::array creation
[edit] ostream_joiner
[edit] Simple random number generation facilities
A per-thread engine of type std::default_random_engine, initialized to an unpredictable state, is maintained for each thread and used by the functions below.
| Defined in header <experimental/random> | |
|---|---|
| randint | generates a random integer in the specified range (function template) [edit] |
| reseed | reseeds the per-thread random engine (function) [edit] |
| Defined in header <experimental/algorithm> | |
| sample | selects n random elements from a sequence (function template) |
| shuffle | randomly re-orders elements in a range (function template) |
[edit] Feature test macros
| Defined in header <experimental/type_traits> | |
|---|---|
| __cpp_lib_experimental_logical_traits | a value of at least 201511 indicates that the logical operator type traits are supported (macro constant) |
| __cpp_lib_experimental_detect | a value of at least 201505 indicates that the detection idiom is supported (macro constant) |
| Defined in header <experimental/propagate_const> | |
| __cpp_lib_experimental_propagate_const | a value of at least 201505 indicates that propagate_const is supported (macro constant) |
| Defined in header <experimental/functional> | |
| __cpp_lib_experimental_not_fn | a value of at least 201406 indicates that not_fn is supported (macro constant) |
| Defined in header <experimental/memory> | |
| __cpp_lib_experimental_observer_ptr | a value of at least 201411 indicates that observer_ptr is supported (macro constant) |
| Defined in header <experimental/array> | |
| __cpp_lib_experimental_make_array | a value of at least 201505 indicates that make_array is supported (macro constant) |
| Defined in header <experimental/iterator> | |
| __cpp_lib_experimental_ostream_joiner | a value of at least 201411 indicates that ostream_joiner is supported (macro constant) |
| Defined in header <experimental/vector> | |
| __cpp_lib_experimental_erase_if | a value of at least 201411 indicates that uniform container erasure is supported (macro constant) |
| Defined in header <experimental/numeric> | |
| __cpp_lib_experimental_gcd_lcm | a value of at least 201411 indicates that gcd and lcm are supported (macro constant) |
| Defined in header <experimental/random> | |
| __cpp_lib_experimental_randint | a value of at least 201511 indicates that randint and related functions are supported (macro constant) |
| Defined in header <experimental/source_location> | |
| __cpp_lib_experimental_source_location | a value of at least 201505 indicates that source_location is supported (macro constant) |
[edit] Merged into C++17
The following components of the library fundamentals v2 have been adopted into the C++17 standard.
| Defined in header <experimental/type_traits> | |
|---|---|
| void_t | variadic alias template for void(alias template) |
| Defined in header <experimental/type_traits> | |
| conjunction | variadic logical AND metafunction (class template) |
| disjunction | variadic logical OR metafunction (class template) |
| negation | logical NOT metafunction (class template) |
| Defined in header <experimental/functional> | |
| not_fn | creates a function object that returns the complement of the result of the function object it holds (function template) [edit] |
| Defined in header <experimental/numeric> | |
| gcd | constexpr function template returning the greatest common divisor of two integers (function template) [edit] |
| lcm | constexpr function template returning the least common multiple of two integers (function template) [edit] |
[edit] Merged into C++20
The following components of the library fundamentals v2 have been adopted into the C++20 standard.
[edit] Uniform container erasure
| Defined in header <experimental/string> | |
|---|---|
| erase (std::basic_string) | erases all elements equal to a specific value from a std::basic_string (function template) |
| erase_if (std::basic_string) | erases all elements satisfying a predicate from a std::basic_string (function template) |
| Defined in header <experimental/deque> | |
| erase (std::deque) | erases all elements equal to a specific value from a std::deque (function template) |
| erase_if (std::deque) | erases all elements satisfying a predicate from a std::deque (function template) |
| Defined in header <experimental/vector> | |
| erase (std::vector) | erases all elements equal to a specific value from a std::vector (function template) |
| erase_if (std::vector) | erases all elements satisfying a predicate from a std::vector (function template) |
| Defined in header <experimental/forward_list> | |
| erase (std::forward_list) | erases all elements equal to a specific value from a std::forward_list (function template) |
| erase_if (std::forward_list) | erases all elements satisfying a predicate from a std::forward_list (function template) |
| Defined in header <experimental/list> | |
| erase (std::list) | erases all elements equal to a specific value from a std::list (function template) |
| erase_if (std::list) | erases all elements satisfying a predicate from a std::list (function template) |
| Defined in header <experimental/map> | |
| erase_if (std::map) | erases all elements satisfying a predicate from a std::map (function template) |
| erase_if (std::multimap) | erases all elements satisfying a predicate from a std::multimap (function template) |
| Defined in header <experimental/set> | |
| erase_if (std::set) | erases all elements satisfying a predicate from a std::set (function template) |
| erase_if (std::multiset) | erases all elements satisfying a predicate from a std::multiset (function template) |
| Defined in header <experimental/unordered_map> | |
| erase_if (std::unordered_map) | erases all elements satisfying a predicate from a std::unordered_map (function template) |
| erase_if (std::unordered_multimap) | erases all elements satisfying a predicate from a std::unordered_multimap (function template) |
| Defined in header <experimental/unordered_set> | |
| erase_if (std::unordered_set) | erases all elements satisfying a predicate from a std::unordered_set (function template) |
| erase_if (std::unordered_multiset) | erases all elements satisfying a predicate from a std::unordered_multiset (function template) |