Storing return value from function to const ref

Asked Apr 03 '19 at 17:49

Active Apr 03 '19 at 17:49

Viewed 42 times

Function GetVec return std::vector. Then I store the returned value into the const ref. Does the returned value stored in const ref get destroyed in next line. I was in the impression it wont.


#include <vector>
#include <iostream>

std::vector<int> GetVec(){
  std::vector<int> vec;

  vec.push_back(1);
  vec.push_back(2);
  vec.push_back(3);

  return vec;
}


void print(const std::vector<int>& arg){
  for(const auto& id : arg){
    std::cout <<id << ",";
  }
  std::cout << std::endl;
}

int main(){
  const std::vector<int>& ret_val = GetVec();

  // is content of ret_val undefined here?
  print(ret_val);
}

Output :

1,2,3,

asked Apr 03 '19 at 17:49

mato

This is legal code. The `const ref` will remain valid in its own scope, which for your case is the entire `main()` – cplusplusrat Apr 03 '19 at 17:51
[Does a const reference class member prolong the life of a temporary?](https://stackoverflow.com/questions/2784262/does-a-const-reference-class-member-prolong-the-life-of-a-temporary) – user4581301 Apr 03 '19 at 17:52
Tell me if the dupe is wrong – Guillaume Racicot Apr 03 '19 at 17:58
In your example, ret_val vector is destroyed when your main class ends. – StackAttack Apr 03 '19 at 18:07

Storing return value from function to const ref

0 Answers0