std::deque::shrink_to_fit

void shrink_to_fit();		(since C++11)

Requests the removal of unused capacity.

It is a non-binding request to reduce the memory usage without changing the size of the sequence. It depends on the implementation whether the request is fulfilled.

All iterators and references are invalidated. Past-the-end iterator is also invalidated.

Parameters

(none)

Type requirements
- `T` must meet the requirements of MoveInsertable.

Return value

(none)

Complexity

At most linear in the size of the container.

Notes

If an exception is thrown other than by T's move constructor, there are no effects.

Example

Run this code

#include <deque>
 
int main() {
    std::deque<int> nums(1000, 42);
    nums.push_front(1);
    nums.pop_front();
 
    nums.clear();
 
    // nums now contains no items, but it may still be holding allocated memory. 
    // Calling shrink_to_fit may free any unused memory.
    nums.shrink_to_fit();
}

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Technical Specifications

array (C++11)
vector
deque
forward_list (C++11)
list
set
multiset
map
multimap
unordered_set (C++11)
unordered_multiset (C++11)
unordered_map (C++11)
unordered_multimap (C++11)
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span (C++20)

Member functions
deque::deque
deque::~deque
deque::operator=
deque::assign
deque::get_allocator
Element access
deque::front
deque::back
Iterators
deque::begindeque::cbegin (C++11)
deque::enddeque::cend (C++11)
deque::rbegindeque::crbegin (C++11)
deque::renddeque::crend (C++11)
Capacity
deque::empty
deque::size
deque::max_size
deque::shrink_to_fit
Modifiers
deque::clear
deque::insert
deque::emplace
deque::erase
deque::push_front
deque::emplace_front
deque::pop_front
deque::push_back
deque::emplace_back
deque::pop_back
deque::resize
deque::swap
Deduction guides(C++17)