Difference between push_back and emplace_back in the case of a temporary value

Asked Apr 22 '13 at 14:38

Active Apr 22 '13 at 14:38

Viewed 269 times

Consider this snippet:

#include <vector>

struct A
{
   A(int b): m_b(b) { }

private:
   int m_b;
};

int main()
{
    std::vector<A> vec;

    vec.push_back( A(3) );

    vec.emplace_back( 3 );
}

In that particular case where a temporary value is passed, is there any difference between the 2 calls that a compiler won’t optimize away? Should I prefer one to the other?

asked Apr 22 '13 at 14:38

qdii

12,505
10
59
116

copy and move elision will probably be used on both and they will end up looking the same in the executable. – Tony The Lion Apr 22 '13 at 14:39
1

Just try it. P.S.: You can also do `push_back(3)`, since your constructor is not `explicit` – Andy Prowl Apr 22 '13 at 14:41

Difference between push_back and emplace_back in the case of a temporary value

0 Answers0