std::forward_list<T,Allocator>::pop_front

 

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std::forward_list

Member functions
forward_list::forward_list forward_list::~forward_list forward_list::operator= forward_list::assign forward_list::assign_range (C++23)   forward_list::get_allocator Element access forward_list::front Iterators forward_list::before_beginforward_list::cbefore_begin forward_list::beginforward_list::cbegin forward_list::endforward_list::cend Capacity forward_list::empty forward_list::max_size	Modifiers forward_list::clear forward_list::emplace_front forward_list::push_front forward_list::insert_after forward_list::emplace_after forward_list::erase_after forward_list::insert_range_after (C++23) forward_list::prepend_range (C++23) forward_list::pop_front forward_list::resize forward_list::swap Operations forward_list::merge forward_list::splice_after forward_list::removeforward_list::remove_if forward_list::reverse forward_list::unique forward_list::sort
Non-member functions
operator==operator<=> (C++20) swap(std::forward_list) erase(std::forward_list)erase_if(std::forward_list) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides (C++17)

 

void pop_front();		(since C++11) (constexpr since C++26)

Removes the first element of the container.

If empty() is true, the behavior is undefined.	(until C++26)
If empty() is true: If the implementation is hardened, a contract violation occurs. Moreover, if the contract-violation handler returns under “observe” evaluation semantic, the behavior is undefined. If the implementation is not hardened, the behavior is undefined.	(since C++26)

References and iterators to the erased element are invalidated.

Complexity

Constant.

Example

Run this code

#include <forward_list>
#include <iostream>
 
int main()
{
    std::forward_list<char> chars{'A', 'B', 'C', 'D'};
 
    for (; !chars.empty(); chars.pop_front())
        std::cout << "chars.front(): '" << chars.front() << "'\n";
}

Output:

chars.front(): 'A'
chars.front(): 'B'
chars.front(): 'C'
chars.front(): 'D'

See also

push_front	inserts an element to the beginning (public member function)
front	access the first element (public member function)