std::from_range, std::from_range_t
Defined in header <ranges> | ||
|---|---|---|
struct from_range_t { explicit from_range_t() = default; };
| (since C++23) | |
inline constexpr std::from_range_t from_range {};
| (since C++23) |
std::from_range is a disambiguation tag that can be passed to the constructors of the suitable containers to indicate that the contained member is range constructed.
The corresponding type std::from_range_t can be used in the constructor's parameter list to match the intended tag.
Standard library
The following standard library types use std::from_range_t type in their constructors:
Containers library |
|
|
(C++23) | constructs the vector from a range (public member function of std::vector<T,Allocator>) |
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(C++26) | constructs the inplace_vector from a range (public member function of std::inplace_vector<T,N>) |
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(C++26) | constructs the hive from a range (public member function of std::hive<T,Allocator>) |
|
(C++23) | constructs the deque from a range (public member function of std::deque<T,Allocator>) |
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(C++23) | constructs the forward_list from a range (public member function of std::forward_list<T,Allocator>) |
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(C++23) | constructs the list from a range (public member function of std::list<T,Allocator>) |
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(C++23) | constructs the set from a range (public member function of std::set<Key,Compare,Allocator>) |
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(C++23) | constructs the map from a range (public member function of std::map<Key,T,Compare,Allocator>) |
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(C++23) | constructs the multiset from a range (public member function of std::multiset<Key,Compare,Allocator>) |
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(C++23) | constructs the multimap from a range (public member function of std::multimap<Key,T,Compare,Allocator>) |
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(C++23) | constructs the unordered_set from a range (public member function of std::unordered_set<Key,Hash,KeyEqual,Allocator>) |
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(C++23) | constructs the unordered_map from a range (public member function of std::unordered_map<Key,T,Hash,KeyEqual,Allocator>) |
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(C++23) | constructs the unordered_multiset from a range (public member function of std::unordered_multiset<Key,Hash,KeyEqual,Allocator>) |
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(C++23) | constructs the unordered_multimap from a range (public member function of std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>) |
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(C++23) | constructs the priority_queue from a range (public member function of std::priority_queue<T,Container,Compare>) |
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(C++23) | constructs the queue from a range (public member function of std::queue<T,Container>) |
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(C++23) | constructs the stack from a range (public member function of std::stack<T,Container>) |
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(C++23) | constructs the flat_set from a range (public member function of std::flat_set<Key,Compare,KeyContainer>) |
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(C++23) | constructs the flat_map from a range (public member function of std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>) |
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(C++23) | constructs the flat_multiset from a range (public member function of std::flat_multiset<Key,Compare,KeyContainer>) |
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(C++23) | constructs the flat_multimap from a range (public member function of std::flat_multimap<Key,T,Compare,KeyContainer,MappedContainer>) |
Strings library |
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(C++23) | constructs the basic_string from a range (public member function of std::basic_string<CharT,Traits,Allocator>) |
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_containers_ranges | 202202L | (C++23) | Tagged constructors to construct from container compatible range |
Example
#include <cassert>
#include <string>
int main()
{
#ifdef __cpp_lib_containers_ranges
auto const range = {0x43, 43, 43};
std::string str{std::from_range, range}; // uses tagged constructor
assert(str == "C++");
#endif
}
See also
|
(C++17) | in-place construction tag (tag) |
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(C++23) | indicates that elements of a range are sorted (uniqueness is not required) (tag) |
|
(C++23) | indicates that elements of a range are sorted and unique (tag) |
|
(C++23) | constructs a new non-view object from an input range (function template) |
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