public member function
<list>

std::list::pop_front

void pop_front();
Delete first element
Removes the first element in the list container, effectively reducing its size by one.

This destroys the removed element.

Parameters

none

Return value

none

Example

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// list::pop_front
#include <iostream>
#include <list>

int main ()
{
  std::list<int> mylist;
  mylist.push_back (100);
  mylist.push_back (200);
  mylist.push_back (300);

  std::cout << "Popping out the elements in mylist:";
  while (!mylist.empty())
  {
    std::cout << ' ' << mylist.front();
    mylist.pop_front();
  }

  std::cout << "\nFinal size of mylist is " << mylist.size() << '\n';

  return 0;
}
Output:
Popping out the elements in mylist: 100 200 300
Final size of mylist is 0


Complexity

Constant.

Iterator validity

Iterators, pointers and references referring to the element removed by the function are invalidated.
All other iterators, pointers and reference keep their validity.

Data races

The container is modified.
The first element is modified. Concurrently accessing or modifying other elements is safe.

Exception safety

If the container is not empty, the function never throws exceptions (no-throw guarantee).
Otherwise, it causes undefined behavior.

See also