Namespaces
Variants
Actions

std::inplace_vector<T,N>::try_emplace_back

From cppreference.com
 
 
 
std::inplace_vector
 
template< class... Args >
constexpr pointer try_emplace_back( Args&&... args );
(since C++26)

Conditionally appends an object of type T to the end of the container.

If size() == capacity() is true, there are no effects. Otherwise, appends direct-non-list-initialized with std::forward <Args>(args)... object of type T.

No iterators or references are invalidated, except end(), which is invalidated if the insertion occurs.

[edit] Parameters

args - arguments to forward to the constructor of the element
Type requirements
-T must be EmplaceConstructible into inplace_vector from std::forward <Args>(args)....

[edit] Return value

std::addressof (back()) if size() < capacity(), nullptr otherwise.

[edit] Complexity

Constant.

[edit] Exceptions

Any exception thrown by initialization of inserted element. If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).

[edit] Notes

This section is incomplete
Reason: Explain the purpose of this API.

[edit] Example

Run this code
#include <cassert>
#include <complex>
#include <inplace_vector>
 
int main()
{
 using namespace std::complex_literals;
 using C = std::complex <double>;
 using I = std::inplace_vector <C, 3>;
 auto v = I{1.0 + 2.0i, 3.0 + 4.0i};
 
 C* c = v.try_emplace_back(5.0, 6.0);
 assert (*c == 5.0 + 6.0i);
 assert ((v == I{1.0 + 2.0i, 3.0 + 4.0i, 5.0 + 6.0i}));
 
 c = v.try_emplace_back(7.0, 8.0); // no space => no insertion
 assert (c == nullptr);
 assert ((v == I{1.0 + 2.0i, 3.0 + 4.0i, 5.0 + 6.0i}));
}

[edit] See also

constructs an element in-place at the end
(public member function) [edit]
adds an element to the end
(public member function) [edit]
adds a range of elements to the end
(public member function) [edit]
tries to add a range of elements to the end
(public member function) [edit]
unconditionally constructs an element in-place at the end
(public member function) [edit]
unconditionally adds an element to the end
(public member function) [edit]
removes the last element
(public member function) [edit]
creates a std::back_insert_iterator of type inferred from the argument
(function template) [edit]
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/inplace_vector/try_emplace_back&oldid=175521"

AltStyle によって変換されたページ (->オリジナル) /