STL Preview

Description

Use the latest STL implementation regardless of your C++ version (C++14 ~)

// All implementations are written under C++14 standard semantics
#include "preview/ranges.h"

auto map = preview::views::iota('A', 'E') | 
           preview::views::enumerate | 
           preview::ranges::to<std::map>(); // See notes about CTAD below

std::cout << map[0] << ' '
          << map[1] << ' '
          << map[2] << '\n';
// A B C

preview is standard-conforming, and is compatible with existing STL

// Pre-C++20 iterators are fully compatible
auto floats = std::istringstream{"1.1  2.2\t3.3\v4.4\f55\n66\r7.7  8.8"};
ranges::copy(views::istream<float>(floats), std::ostream_iterator<float>{std::cout, ", "});

// Complex ranges/iterators are also compatible with both pre C++20 and 
// post C++20 std::iterator_traits
auto r = preview::views::iota(0) |
      preview::views::take(10) |
      preview::views::filter([](auto x) { return x % 2 == 0; });

static_assert(std::is_same<
    std::iterator_traits<decltype(r.begin())>::reference,
    int
>::value, "");

Up to C++26 STL are available

void foo(preview::span<int>) {}

int main() {
  // span with C++26 standard
  foo({1, 2, 3});
  
  preview::variant<int, float, double> v{1.0f};
  v.visit([](auto x) {
    // member visit(): C++26 standard
  });
  
  // views::concat
  std::vector<char> v = {'h', 'e', 'l'};
  std::string s = "lo, ";
  preview::string_view sv = "world";
  std::list<char> l = {'!'};

  // hello, world!
  for (auto c : preview::views::concat(v, s, sv, l)) {
    std::cout << c;
  }
  
  // expected
  auto process = [](preview::string_view str) -> preview::expected<int, std::string> {
    return parse_number(str)
      .transform([](double v) { return static_cast<int>(v); })
      .transform_error([](parse_error e) {
        return e == parse_error::invalid_input ? "invalid input" : "overflow";
      });
  };
  std::cout << process("42").value_or(-1) << '\n;'; // 42
  std::cout << process("inf").value_or(-1) << '\n'; // -1
}

Compiler Support

Note: Requires C++14 or later

Compiler	Minimum version tested	Maximum version tested
MSVC	19.16.27051.0 (Visual Studio 2017)	19.40.33811.0 (Visual Studio 2022)
gcc	9.5.0	13.1.0
clang	11.1.0	15.0.7
Apple clang	14.0.0.14000029	15.0.0.15000040 (Silicon)
Android NDK	r18 (clang 7.0)	r26 (clang 17.0.2)
Emscripten	3.1.20 (clang 16.0.0)	latest(3.1.61) (clang 19.0.0)
MinGW	13.1.0	14.2.0
Intel C++	?	icx 2024.2

Media

CppCon2024

C++17/20/23/26 for old C++ Developers - STL Preview
Best Poster Award

Build & Install

CMake

Copy this repository under your project and use add_subdirectory

add_subdirectory(path/to/preview)
target_link_libraries(your-project INTERFACE preview)

Non-CMake

Although it is not recommended, you can just copy & paste files under include/ into your project.

Note: Without CMake configuration, heuristic compiler/STL checks will be performed.

Installation

With the reason stated in Non-CMake, installation is possible but not recommended.

Implementation Status

Implementation available in C++14 ~ :

Header	Total	C++26


algorithm
any
array
bit
concepts
cstddef
expected
functional
iterator
mdspan
memory
numbers
numeric
optional
random
ranges
span
string_view		*
tuple
type_traits
utility
variant

atomic
barrier
charconv
chrono
cmath
compare
coroutine	N/A
debugging
exception
execution
flat_map
flat_set
format
filesystem	N/A
hazard_pointer
inplace_vector
latch
linalg
memory_resource
mutex
new
print
rcu
semaphore
shared_mutex
stop_token
string
source_location	N/A
syncstream
spanstream
stacktrace	N/A
text_encoding
thread
version

Detailed status

Features

Description

: C++YY standard implemented in C++XX
: C++YY standard, not implemented yet
If the implementation is impossible(i.e., needs compiler support / hardware info) it is marked as N/A
Some features are working in progress
Introduced: First introduced version
Revision: Behavior changed/updated version

Headers

`<algorithm>`

	Introduced	Revision
`search`
`clamp`
`for_each_n`
`sample`
`shift_left`
`shift_right`
`ranges::in_fun_result`
`ranges::in_in_result`
`ranges::in_out_result`
`ranges::in_in_out_result`
`ranges::in_out_out_result`
`ranges::min_max_result`
`ranges::in_found_result`
`ranges::in_value_result`
`ranges::out_value_result`
`ranges::all_of`
`ranges::any_of`
`ranges::none_of`
`ranges::for_each`
`ranges::for_each_n`
`ranges::count`
`ranges::count_if`
`ranges::mismatch`
`ranges::find`
`ranges::find_if`
`ranges::find_if_not`
`ranges::find_last`
`ranges::find_last_if`
`ranges::find_last_if_not`
`ranges::find_end`
`ranges::find_first_of`
`ranges::adjacent_find`
`ranges::search`
`ranges::search_n`
`ranges::contains`
`ranges::contains_subrange`
`ranges::starts_with`
`ranges::ends_with`
`ranges::fold_left`
`ranges::fold_left_first`
`ranges::fold_right`
`ranges::fold_right_last`
`ranges::fold_left_with_iter`
`ranges::fold_left_first_with_iter`
`ranges::copy`
`ranges::copy_if`
`ranges::copy_n`
`ranges::copy_backward`
`ranges::move`
`ranges::move_backward`
`ranges::fill`
`ranges::fill_n`
`ranges::transform`
`ranges::generate`
`ranges::generate_n`
`ranges::remove`
`ranges::remove_if`
`ranges::remove_copy`
`ranges::remove_copy_if`
`ranges::replace`
`ranges::replace_if`
`ranges::replace_copy`
`ranges::replace_copy_if`
`ranges::swap_ranges`
`ranges::reverse`
`ranges::reverse_copy`
`ranges::rotate`
`ranges::rotate_copy`
`ranges::shift_left`
`ranges::shift_right`
`ranges::sample`
`ranges::shuffle`
`ranges::unique`
`ranges::unique_copy`
`ranges::is_partitioned`
`ranges::partition`
`ranges::partition_copy`
`ranges::stable_partition`
`ranges::partition_point`
`ranges::is_sorted`
`ranges::is_sorted_until`
`ranges::sort`
`ranges::partial_sort`
`ranges::partial_sort_copy`
`ranges::stable_sort`
`ranges::nth_element`
`ranges::lower_bound`
`ranges::upper_bound`
`ranges::binary_search`
`ranges::equal_range`
`ranges::merge`
`ranges::inplace_merge`
`ranges::includes`
`ranges::set_difference`
`ranges::set_intersection`
`ranges::set_symmetric_difference`
`ranges::set_union`
`ranges::is_heap`
`ranges::is_heap_until`
`ranges::make_heap`
`ranges::push_heap`
`ranges::pop_heap`
`ranges::sort_heap`
`ranges::max`
`ranges::max_element`
`ranges::min`
`ranges::min_element`
`ranges::minmax`
`ranges::minmax_element`
`ranges::clamp`
`ranges::equal`
`ranges::lexicographical_compare`
`ranges::is_permutation`
`ranges::next_permutation`
`ranges::prev_permutation`

`<any>`

	Introduced	Revision
`any`	*
`bad_any_cast`
`swap(any)`
`make_any`
`any_cast`

Notes
- preview::any
  - preview::any is an alias of std::any if using C++17 or later to prevent implicit construction of std::any from preview::any and vice-versa. See any.h for more detail.

`<array>`

	Introduced	Revision
`to_array`

`<atomic>`

	Introduced	Revision
`atomic_ref`
`atomic_signed_lock_free`
`atomic_unsigned_lock_free`
`atomic_wait`
`atomic_wait_explicit`
`atomic_notify_one`
`atomic_notify_all`
`atomic_flag_test`
`atomic_flag_test_explicit`
`atomic_flag_wait`
`atomic_flag_wait_explicit`
`atomic_flag_notify_one`
`atomic_flag_notifly_all`
`atomic_fetch_max`
`atomic_fetch_max_explicit`
`atomic_fetch_min`
`atomic_fetch_min_explicit`

`<barrier>`

	Introduced	Revision
`barrier`

`<bit>`

	Introduced	Revision
`endian`
`bit_cast`
`byteswap`
`has_single_bit`
`bit_ceil`
`bit_floor`
`bit_width`
`rotl`
`rotr`
`countl_zero`
`countl_one`
`countr_zero`
`countr_one`
`popcount`

`<charconv>`

	Introduced	Revision
`chars_format`
`from_chars_result`
`to_chars_result`
`from_chars`
`to_chars`

`<chrono>`

	Introduced	Revision
`std::chrono::duration`
`std::chrono::time_point`
`clock_time_conversion`
`is_clock`
`utc_clock`
`tai_clock`
`gps_clock`
`file_clock`
`local_t`
`last_spec`
`day`
`month`
`year`
`weekday`
`weekday_indexed`
`weekday_last`
`month_day`
`month_day_last`
`month_weekday`
`month_weekday_last`
`year_month`
`year_month_day`
`year_month_day_last`
`year_month_weekday`
`year_month_weekday_last`
`hh_mm_ss`
`tzdb`
`tzdb_list`
`tzdb_zone`
`get_tzdb`
`get_tzdb_list`
`reload_tzdb`
`remote_version`
`locate_zone`
`sys_info`
`local_info`
`choose`
`zoned_traits`
`zoned_time`
`time_zone_link`
`nonexistent_local_time`
`ambiguous_local_time`
`leap_second`
`leap_second_info`
`get_leap_second_info`
`is_am` `is_pm`
`make_12` `make_24`

`<cmath>`

	Introduced	Revision
`assoc_laguerre`
`assoc_legendre`
`beta`
`comp_ellint_1`
`comp_ellint_2`
`comp_ellint_3`
`cyl_bessel_i`
`cyl_bessel_j`
`cyl_bessel_k`
`cyl_neumann`
`ellint_1`
`ellint_2`
`ellint_3`
`expint`
`hermite`
`legendre`
`laguerre`
`riemann_zeta`
`sph_bessel`
`sph_legendre`
`sph_neumann`
`hypot(x, y, z)`

`<compare>`

N/A

`<concepts>`

	Introduced	Revision
`same_as`
`derived_from`
`convertible_to`
`common_reference_with`
`common_with`
`integral`
`signed_integral`
`unsigned_integral`
`floating_point`
`assignable_from`
`swappable`
`destructible`
`constructible_from`
`default_initializable`
`move_constructible`
`copy_constructible`
`equality_comparable`
`equality_comparable_with`
`totally_ordered`
`movable`
`copyable`
`semiregular`
`regular`
`invocable`
`regular_invocable`
`predicate`
`relation`
`equivalence_relation`
`strict_weak_order`
`ranges::swap`

`<coroutine>`

N/A

`<cstddef>`

	Introduced	Revision
`byte`
`to_integer`

`<debugging>`

	Introduced	Revision
`breakpoint`
`breakpoint_if_debugging`
`is_debugger_present`

`<exception>`

	Introduced	Revision
`uncaught_exceptions`	(N/A)

`<expected>`

	Introduced	Revision
`expected`
`unexpected`
`bad_expected_access`
`unexpect` `unexpect_t`

`<execution>`

N/A

`<flat_map>`

	Introduced	Revision
`flat_map`
`flat_multimap`
`sorted_unique` `sorted_unique_t`
`sorted_equivalent` `sorted_equivalent_t`

`<flat_set>`

	Introduced	Revision
`flat_set`
`flat_multiset`

`<format>`

	Introduced	Revision
`formatter`
`basic_format_parse_context`
`basic_format_context`
`basic_format_arg`
`basic_format_args`
`basic_format_string`
`format_error`
`format`
`format_to`
`format_to_n`
`formatted_size`
`vformat`
`vformat_to`
~~`visit_format_arg`~~		deprecated in C++26
`make_format_args`
`make_wformat_args`
`formattable`
`range_format`
`range_formatter`
`formatter<pair-or-tuple>`
`formatter<range>`
`format_kind`
`enable_nonlocking_formatter_optimization`
`runtime_format`

`<filesystem>`

N/A

`<functional>`

	Introduced	Revision
`reference_wrapper`		*
`default_searcher`
`boyer_moore_searcher`
`boyer_moore_horspool_searcher`
`invoke`
`not_fn`
`bind_front`
`identity`
`unwrap_reference`
`unwrap_ref_decay`
`ranges::equal_to`
`ranges::not_equal_to`
`ranges::greater`
`ranges::less`
`ranges::greater_equal`
`ranges::less_equal`
`compare_three_way`
`ranges::three_way`
`invoke_r`
`bind_back`
`move_only_function`
`copyable_function`
`function_ref`

Notes
- reference_wrapper
  - Non-standard member function operator*() is defined only for the purpose of mixed use with std::invoke.
  - Before C++20, preview::reference_wrapper cannot be used in deduced context of std::reference_wrapper. In sucn case, non-standard member function to_std() can be used.
```
template<typename T>
void foo(std::reference_wrapper<T> x) {}

int main() {
  int x = 10;
  auto ref = preview::ref(x);
  foo(ref); // Compile error before C++20
  foo(ref.to_std());

  std::cout << std::boolalpha << (ref == 10) << std::endl;
}
```

`<hazard_pointer>`

	Introduced	Revision
`hazard_pointer_obj_base`
`hazard_pointer`
`make_hazard_pointer`

`<inplace_vector>`

	Introduced	Revision
`inplace_vector`

`<iterator>`

	Introduced	Revision
`contiguous_iterator_tag`	*
`indirectly_readable`
`indirectly_writable`
`weakly_incrementable`
`incrementable`
`input_or_output_iterator`
`sentinel_for`
`sized_sentinel_for`
`input_iterator`
`output_iterator`
`forward_iterator`
`bidirectional_iterator`
`random_access_iterator`
`contiguous_iterator`	*
`indirectly_unary_invocable`
`indirectly_regular_unary_invocable`
`indirect_unary_predicate`
`indirect_binary_predicate`
`indirect_equivalence_relation`
`indirect_strict_weak_order`
`indirectly_movable`
`indirectly_movable_storable`
`indirectly_copyable`
`indirectly_copyable_storable`
`indirectly_swappable`
`indirectly_comparable`
`permutable`
`mergeable`
`sortable`
`indirect_result_t`
`projected`		*
`projected_value_t`
`incrementable_traits`
`indirectly_readable_traits`
`iter_value_t` `iter_reference_t`
`iter_const_reference_t`
`iter_difference_t`
`iter_rvalue_reference_t`
`iter_common_reference_t`
`iterator_traits`
`move_sentinel`
`basic_const_iterator`
`const_iterator`
`const_sentinel`
`common_iterator`
`default_sentinel_t` `default_sentinel`
`counted_iterator`
`unreachable_sentinel_t` `unreachable_sentinel`
`iter_move`
`iter_swap`
`make_const_iterator` `make_const_sentinel`
`ranges::advance`
`ranges::distance`
`ranges::next`
`ranges::prev`
`size(C)`
`ssize(C)`
`empty(C)`
`data(C)`

Notes
- contiguous_iterator_tag
  - Alias to std::contiguous_iterator_tag if defined, preview::detail::pseudo_contiguous_iterator_tag otherwise.
- contiguous_iterator<I>
  - May incorrectly evaluates to true for some random_access_iterator if I::iterator_category does not satisfy derived_from<contiguous_iterator_tag>(typically before C++20)
  - Following pre-C++20 iterators explicitly evaluates to false
    - std::vector<bool>::xxx_iterator
    - std::deque<T>::xxx_iterator
- projected
  - Indirect layer doesn't work without using concepts. Check preview::projectable before using preview::projected directly.

`<latch>`

	Introduced	Revision
`latch`

`<linalg>`

	Introduced	Revision
`layout_blas_packed`
`scaled_accessor`
`conjugated_accessor`
`layout_transpose`
`column_major` `column_major_t`
`row_major` `row_major_t`
`upper_triangle` `upper_triangle_t`
`lower_triangle` `lower_triangle_t`
`implicit_unit_diagonal` `implicit_unit_diagonal_t`
`explicit_unit_diagonal` `explicit_unit_diagonal_t`
`scaled`
`conjugated`
`transposed`
`conjugated_transposed`
`setup_givens_rotation`
`apply_givens_rotation`
`swap_elements`
`scale`
`copy`
`add`
`dot` `dotc`
`vector_sum_of_squares`
`vector_two_norm`
`vector_abs_sum`
`vector_idx_abs_max`
`matrix_frob_norm`
`matrix_one_norm`
`matrix_inf_norm`
`matrix_vector_product`
`symmetric_matrix_vector_product`
`hermitian_matrix_vector_product`
`triangular_matrix_vector_product`
`triangular_matrix_vector_solve`
`matrix_rank_1_update`
`matrix_rank_1_update_c`
`symmetric_matrix_rank_1_update`
`hermitian_matrix_rank_1_update`
`symmetric_matrix_rank_2_update`
`hermitian_matrix_rank_2_update`
`matrix_product`
`symmetric_matrix_product`
`hermitian_matrix_product`
`triangular_matrix_product`
`triangular_matrix_left_product`
`triangular_matrix_right_product`
`symmetric_matrix_rank_k_update`
`hermitian_matrix_rank_k_update`
`symmetric_matrix_rank_2k_update`
`hermitian_matrix_rank_2k_update`
`triangular_matrix_matrix_left_solve`
`triangular_matrix_matrix_right_solve`

`<mdspan>`

	Introduced	Revision
`mdspan`
`extents`
`layout_left`
`layout_right`
`layout_stride`
`default_accessor`
`dextents`
`layout_left_padded`
`layout_right_padded`
`strided_slice`
`dims`
`submdspan`
`submdspan_extents`
`submdspan_mapping_result`
`full_extent` `full_extent_t`

`<memory>`

	Introduced	Revision
`pointer_traits`
`aligned_alloc`
`destroy_at`
`destroy`
`destroy_n`
`xxx_pointer_cast`
`uninitialized_default_construct`
`uninitialized_default_construct_n`
`uninitialized_move`
`uninitialized_move_n`
`uninitialized_value_construct`
`uninitialized_value_construct_n`
`atomic<shared_ptr>`
`atomic<unique_ptr>`
`assume_aligned`
`construct_at`
`make_shared_for_overwrite`
`make_unique_for_overwrite`
`allocate_shared_for_overwrite`
`to_address`	*
`uses_allocator_construction_args`
`make_obj_using_allocator`
`uninitialized_construct_using_allocator`
`operator<<(std::unique_ptr)`
`ranges::construct_at`
`ranges::destroy`
`ranges::destroy_n`
`ranges::destroy_at`
`ranges::uninitialized_copy`
`ranges::uninitialized_copy_n`
`ranges::uninitialized_fill`
`ranges::uninitialized_fill_n`
`ranges::uninitialized_move`
`ranges::uninitialized_move_n`
`ranges::uninitialized_default_construct`
`ranges::uninitialized_default_construct_n`
`ranges::uninitialized_value_construct`
`ranges::uninitialized_value_construct_n`
`allocation_result`
`inout_ptr` `inout_ptr_t`
`out_ptr` `out_ptr_t`
`start_lifetime_as` `start_lifetime_as_array`
`owner_hash`
`owner_equal`

Notes
- to_address
  - If std::pointer_traits::to_address is available, it is used before preview::pointer_traits::to_address.
    - ⚠️ std::pointer_traits::to_address is not sfinae-friendly until MSVC 2022, so not used.

`<memory_resource>`

N/A

`<mutex>`

	Introduced	Revision
`scoped_lock`

`<new>`

	Introduced	Revision
`align_val_t`
`hardware_destructive_interference_size`
`hardware_constructive_interference_size`
`launder`
`destroying_delete` `destroying_delete_t`

`<numbers>`

	Introduced	Revision
`e`
`log2e`
`log10e`
`pi`
`inv_pi`
`inv_sqrtpi`
`ln2`
`ln10`
`sqrt2`
`sqrt3`
`inv_sqrt3`
`egamma`
`phi`

`<numeric>`

	Introduced	Revision
`exclusive_scan`
`transform_exclusive_scan`
`inclusive_scan`
`transform_inclusive_scan`
`gcd`
`lcm`
`reduce`
`transform_reduce`
`midpoint`
`ranges::iota`
`add_sat`
`sub_sat`
`mul_sat`
`div_sat`
`saturate_cast`

`<print>`

	Introduced	Revision
`print`
`println`
`vprint_unicode`
`vprint_unicode_buffered`
`vprint_nonunicode`
`vprint_nonunicode_buffered`

`<optional>`

	Introduced	Revision
`optional`		*
`bad_optional_access`
`std::hash<optional>`
`nullopt`	*
`nullopt_t`	*
`swap(optional)`
`make_optional`

Notes
- nullopt, nullopt_t
  - std::nullopt is used if available, preview::nullopt otherwise.
- C++26
  - P3168 (R2)

`<random>`

	Introduced	Revision
`uniform_random_bit_generator`

`<ranges>`

	Introduced	Revision
`ranges::range`
`ranges::borrowed_range`
`ranges::approximately_sized_range`
`ranges::sized_range`
`ranges::view`
`ranges::input_range`
`ranges::output_range`
`ranges::forward_range`
`ranges::bidirectional_range`
`ranges::random_access_range`
`ranges::contiguous_range`
`ranges::common_range`
`ranges::viewable_range`
`ranges::constant_range`
`ranges::to`	*
`ranges::iterator_t`
`ranges::const_iterator_t`
`ranges::sentinel_t`
`ranges::const_sentinel_t`
`ranges::range_difference_t`
`ranges::range_size_t`
`ranges::range_value_t`
`ranges::range_refernce_t`
`ranges::range_const_reference_t`
`ranges::range_rvalue_reference_t`
`ranges::range_common_reference_t`
`ranges::view_interface`
`ranges::subrange`
`ranges::dangling`
`ranges::borrowed_iterator_t`
`ranges::borrowed_subrange_t`
`ranges::range_adaptor_closure`
`ranges::empty_view` `views::empty`
`ranges::single_view` `views::single`
`ranges::iota_view` `views::iota`
`ranges::iota_view` `views::iota`
`ranges::basic_istream_view` `views::istream`
`ranges::repeat_view` `views::repeat`
`ranges::cartesian_product_view` `views::cartesian_product`
`ranges::cache_latest_view` `views::cache_latest`
`ranges::to_input_view` `views::to_input`
`views::all_t` `views::all`
`ranges::ref_view`
`ranges::owning_view`
`ranges::filter_view` `views::filter`
`ranges::transform_view` `views::transform`
`ranges::take_view` `views::take`
`ranges::take_while_view` `views::take_while`
`ranges::drop_view` `views::drop`
`ranges::drop_while_view` `views::drop_while`
`ranges::join_view` `views::join`
`ranges::lazy_split_view` `views::lazy_split`
`ranges::split_view` `views::split`
`views::counted`
`ranges::common_view` `views::common`
`ranges::reverse_view` `views::reverse`
`ranges::as_const_view` `views::as_const`
`ranges::as_rvalue_view` `views::as_rvalue`
`ranges::elements_view` `views::elements`
`ranges::keys_view` `views::keys`
`ranges::values_view` `views::values`
`ranges::enumerate_view` `views::enumerate`
`ranges::zip_view` `views::zip`
`ranges::zip_transform_view` `views::zip_transform`
`ranges::adjacent_view` `views::adjacent`
`ranges::adjacent_transform_view` `views::adjacent_transform`
`ranges::join_with_view` `views::join_with`
`ranges::stride_view` `views::stride`
`ranges::slide_view` `views::slide`
`ranges::chunk_view` `views::chunk`
`ranges::chunk_by_view` `views::chunk_by`
`ranges::concat_view` `views::concat`	*
`ranges::begin`
`ranges::end`
`ranges::cbegin`
`ranges::cend`
`ranges::crbegin`
`ranges::crend`
`ranges::reserve_hint`
`ranges::size`
`ranges::ssize`
`ranges::empty`
`ranges::data`
`ranges::cdata`
`ranges::subrange_kind`
`ranges::from_range_t` `ranges::from_range`

Notes
- ranges::to
  - CTAD for Args... may be incorrect before C++17
  - Equipped with C++23 conversions(e.g., pair-like -> std::pair)
- ranges::concat_view
  - Implemented before standardization
  - Needs update

`<rcu>`

	Introduced	Revision
`rcu_obj_base`
`rcu_domain`
`rcu_default_domain`
`rcu_synchronize`
`rcu_barrier`
`rcu_retire`

`<semaphore>`

	Introduced	Revision
`counting_semaphore`
`binary_semaphore`

`<shared_mutex>`

	Introduced	Revision
`shared_mutex`

`<stop_token>`

	Introduced	Revision
`stop_token`
`stop_source`
`stop_callback`
`nostopstate_t`
`nostopstate`

`<string>`

	Introduced	Revision
`erase(std::basic_string)`
`erase_if(std::basic_string)`
`basic_string`

`<string_view>`

	Introduced	Revision
`basic_string_view`		*
`std::hash<basic_string_view>`
`operator""_sv`

Notes
- C++26
  - P2591 (R5)
  - P2697 (R1)
    - Implemented as preview::basic_string_view::operator bitset
  - P2495 (R3)
    - Implemented as preview::basic_string_view::operator string-streams
    - Memory allocation is performed (conversion to std::basic_string)

`<source_location>`

N/A

	Introduced	Revision
`source_location`

`<syncstream>`

	Introduced	Revision
`basic_syncbuf`
`basic_osyncstream`
`std::swap(basic_syncbuf)`

`<span>`

	Introduced	Revision
`span`
`dynamic_extent`
`as_bytes`
`as_writable_bytes`

`<spanstream>`

	Introduced	Revision
`basic_spanbuf`
`basic_ispanstream`
`basic_ospanstream`
`basic_spanstream`

`<stacktrace>`

	Introduced	Revision
`stacktrace_entry`
`basic_stacktrace`
`hash<stracktrace_entry>`
`hash<basic_stacktrace>`

`<text_encoding>`

	Introduced	Revision
`text_encoding`

`<thread>`

	Introduced	Revision
`jthread`

`<tuple>`

	Introduced	Revision
`apply`
`make_from_tuple`
`tuple_like` `pair_like`
`basic_common_reference<tuple-like>`
`common_type<tuple-like>`
`formatter<tuple-like>`

`<type_traits>`

	Introduced	Revision
`common_type`
`bool_constant`
`has_unique_object_representations`	N/A
`is_aggregate`	N/A
`is_swappable_with` `is_swappable`...
`is_invocable`
`invoke_result`
`void_t`
`conjunction`
`disjunction`
`negation`
`common_reference` `basic_common_reference`
`is_bounded_array`
`is_unbounded_array`
`is_scoped_enum`	N/A
`is_constant_evaluated`	N/A
`is_corresponding_member`	N/A
`is_layout_compatible`	N/A
`is_nothrow_convertible`
`is_pointer_interconvertible_base_of`	N/A
`is_pointer_interconvertible_with_class`	N/A
`remove_cvref`
`type_identity`
`is_implicit_lifetime`	N/A
`is_scoped_enum`	N/A
`reference_converts_from_temporary`	N/A
`reference_constructs_from_temporary`	N/A
`is_within_lifetime`	N/A
`is_virtual_base_of`

Notes

common_type

If common_type fails to define member typedef type, it falls back to std::common_type

struct common_a {};
struct common_b {};
struct common_c {};

template<>
struct std::common_type<common_a, common_b> {
  using type = common_c;
};

// fallback to std::common_type for user specialization types
static_assert(std::is_same_v<preview::common_type_t<common_a, common_b>, common_c>);

// MSVC and GCC (before C++23) does not satisfy C++23 standard for std::common_type<tuple-like>  
static_assert(std::is_same_v<
    std::common_type_t<std::tuple<int, int>, std::pair<int, double>>, 
    std::pair<int, int>>);

// Since std::common_type does not satisfy C++23, preview::common_type does not fallback to std::common_type
static_assert(std::is_same_v<
    preview::common_type_t< std::tuple<int, int>, std::pair<int, double>>, 
    std::pair<int, double>>);

`<utility>`

	Introduced	Revision
`as_const`
`in_place` `in_place_t`
`cmp_equal`...
`in_range`
`forward_like`
`to_underlying`
`unreachable`
`nontype` `nontype_t`

`<variant>`

	Introduced	Revision
`variant`
`monostate`
`bad_variant_access`
`variant_size`
`variant_alternative`
`std::hash<variant>`
`variant_npos`
`visit`
`get_if`

`<version>`

	Introduced	Revision

Name		Name	Last commit message	Last commit date
Latest commit History 116 Commits
.github/workflows		.github/workflows
.vscode		.vscode
cmake		cmake
include/preview		include/preview
media		media
test		test
.cursorignore		.cursorignore
.gitignore		.gitignore
CMakeLists.txt		CMakeLists.txt
LICENSE.txt		LICENSE.txt
README.md		README.md
logo.png		logo.png

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Description

Compiler Support

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Implementation Status

Detailed status

Features

Headers

<algorithm>

<any>

<array>

<atomic>

<barrier>

<bit>

<charconv>

<chrono>

<cmath>

<compare>

<concepts>

<coroutine>

<cstddef>

<debugging>

<exception>

<expected>

<execution>

<flat_map>

<flat_set>

<format>

<filesystem>

<functional>

<hazard_pointer>

<inplace_vector>

<iterator>

<latch>

<linalg>

<mdspan>

<memory>

<memory_resource>

<mutex>

<new>

<numbers>

<numeric>

<print>

<optional>

<random>

<ranges>

<rcu>

<semaphore>

<shared_mutex>

<stop_token>

<string>

<string_view>

<source_location>

<syncstream>

<span>

<spanstream>

<stacktrace>

<text_encoding>

<thread>

<tuple>

<type_traits>

<utility>

<variant>

<version>

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`<algorithm>`

`<any>`

`<array>`

`<atomic>`

`<barrier>`

`<bit>`

`<charconv>`

`<chrono>`

`<cmath>`

`<compare>`

`<concepts>`

`<coroutine>`

`<cstddef>`

`<debugging>`

`<exception>`

`<expected>`

`<execution>`

`<flat_map>`

`<flat_set>`

`<format>`

`<filesystem>`

`<functional>`

`<hazard_pointer>`

`<inplace_vector>`

`<iterator>`

`<latch>`

`<linalg>`

`<mdspan>`

`<memory>`

`<memory_resource>`

`<mutex>`

`<new>`

`<numbers>`

`<numeric>`

`<print>`

`<optional>`

`<random>`

`<ranges>`

`<rcu>`

`<semaphore>`

`<shared_mutex>`

`<stop_token>`

`<string>`

`<string_view>`

`<source_location>`

`<syncstream>`

`<span>`

`<spanstream>`

`<stacktrace>`

`<text_encoding>`

`<thread>`

`<tuple>`

`<type_traits>`

`<utility>`

`<variant>`

`<version>`

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