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

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.

Parameters

Return value

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

Complexity

Constant.

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

Notes

Example

#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}));
}

See also