std::inplace_vector<T,N>::reserve

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

hive (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::inplace_vector

Member types
Member functions
inplace_vector::inplace_vector inplace_vector::~inplace_vector    inplace_vector::operator= inplace_vector::assign inplace_vector::assign_range Size and capacity inplace_vector::empty inplace_vector::size inplace_vector::max_size inplace_vector::capacity inplace_vector::resize inplace_vector::reserve inplace_vector::shrink_to_fit Iterators inplace_vector::begininplace_vector::cbegin inplace_vector::endinplace_vector::cend inplace_vector::rbegininplace_vector::crbegin inplace_vector::rendinplace_vector::crend	Element access inplace_vector::at inplace_vector::operator[] inplace_vector::front inplace_vector::back inplace_vector::data Modifiers inplace_vector::clear inplace_vector::erase inplace_vector::swap inplace_vector::insert inplace_vector::insert_range inplace_vector::emplace inplace_vector::emplace_back inplace_vector::try_emplace_back inplace_vector::unchecked_emplace_back inplace_vector::push_back inplace_vector::try_push_back inplace_vector::unchecked_push_back inplace_vector::pop_back inplace_vector::append_range inplace_vector::try_append_range
Non-member functions
erase(std::inplace_vector)erase_if(std::inplace_vector) swap(std::inplace_vector)	operator==operator<=>

 

static constexpr void reserve( size_type new_cap );		(since C++26)

See More

Does nothing, except that may throw std::bad_alloc. The request to increase the capacity (i.e., the internal storage size) is ignored because std::inplace_vector<T, N> is a fixed-capacity container.

Parameters

new_cap

-

new capacity of the inplace_vector, in number of elements

Return value

(none)

Complexity

Constant.

Exceptions

std::bad_alloc if new_cap > capacity() is true.

Notes

This function exists for compatibility with vector-like interfaces.

Example

Run this code

#include <cassert>
#include <inplace_vector>
#include <iostream>

int main()
{
    std::inplace_vector<int, 4> v{1, 2, 3};
    assert(v.capacity() == 4 && v.size() == 3);

    v.reserve(2); // does nothing
    assert(v.capacity() == 4 && v.size() == 3);

    try
    {
        v.reserve(13); // throws, because requested capacity > N; v is left unchanged
    }
    catch(const std::bad_alloc& ex)
    {
        std::cout << ex.what() << '\n';
    }
    assert(v.capacity() == 4 && v.size() == 3);
}

Possible output:

std::bad_alloc

See also

size	returns the number of elements (public member function)
max_size [static]	returns the maximum possible number of elements (public static member function)
resize	changes the number of elements stored (public member function)
capacity [static]	returns the number of elements that can be held in currently allocated storage (public static member function)
shrink_to_fit [static]	reduces memory usage by freeing unused memory (public static member function)