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std::basic_string<CharT,Traits,Allocator>::reserve

From cppreference.com
< cpp‎ | string‎ | basic string
 
C++
 
Strings library
 
std::basic_string
 
(1)
void reserve( size_type new_cap = 0 );
 (until C++20)
constexpr void reserve( size_type new_cap );
 (since C++20)
void reserve();
 (2) (since C++20)
(deprecated in C++20)
(removed in C++26)
1) Informs a std::basic_string object of a planned change in size, so that it can manage the storage allocation appropriately.
  • If new_cap is greater than the current capacity(), new storage is allocated, and capacity() is made equal or greater than new_cap.
  • If new_cap is less than the current capacity(), this is a non-binding shrink request.
  • If new_cap is less than the current size(), this is a non-binding shrink-to-fit request equivalent to shrink_to_fit()(since C++11).
(until C++20)
  • If new_cap is less than or equal to the current capacity(), there is no effect.
(since C++20)
If a capacity change takes place, all iterators and references, including the past-the-end iterator, are invalidated.
2) A non-binding shrink-to-fit request. After this call, capacity() has an unspecified value greater than or equal to size().

Contents

[edit] Parameters

new_cap - new capacity of the string

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