std::inplace_vector<T,N>::emplace
From cppreference.com
< cpp | container | inplace vector
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Containers library
(C++17)
(C++11)
(C++26)
(C++26)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++23)
(C++23)
(C++23)
(C++23)
(C++20)
(C++23)
Tables
std::inplace_vector
inplace_vector::emplace
template< class... Args >
constexpr iterator emplace( const_iterator position, Args&&... args );
(since C++26)
constexpr iterator emplace( const_iterator position, Args&&... args );
Inserts a new element into the container directly before pos. Typically, the element is constructed uses placement new to construct the element in-place at the location provided by the container. The arguments args... are forwarded to the constructor as std::forward <Args>(args)....
This section is incomplete
[edit] Parameters
pos
-
iterator before which the new element will be constructed
args
-
arguments to forward to the constructor of the element
Type requirements
[edit] Return value
An iterator to the inserted element.
[edit] Complexity
Linear in the distance between pos and end().
[edit] Exceptions
Throws std::bad_alloc if before the invocation size() == capacity(). The function has no effects (strong exception safety guarantee).
Any exception thrown by initialization of inserted element or by any LegacyInputIterator operation. Elements in [0, pos) are not modified.
[edit] Example
Run this code
#include <cassert> #include <inplace_vector> #include <new> #include <utility> int main() { using P = std::pair <int, int>; using I = std::inplace_vector <P, 3>; auto nums = I{{0, 1}, {2, 3}}; auto it = nums.emplace(nums.begin() + 1, -1, -2); assert ((*it == P{-1, -2})); assert ((nums == I{P{0, 1}, {-1, -2}, {2, 3}})); try { nums.emplace(nums.begin(), 1, 3); // throws: no space } catch(const std::bad_alloc & ex) { std::cout << ex.what() << '\n'; } }
Possible output:
std::bad_alloc