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

 

C++

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Standard library headers

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Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

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Ranges library (C++20)

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Symbols index

External libraries

 

Strings library

Null-terminated strings

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Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string

Member functions basic_string::basic_string basic_string::operator= basic_string::assign basic_string::get_allocator Element access basic_string::at basic_string::operator[] basic_string::front (C++11) basic_string::back (C++11) basic_string::data basic_string::c_str basic_string::operator  basic_string_view (C++17) Iterators basic_string::beginbasic_string::cbegin (C++11) basic_string::endbasic_string::cend (C++11) basic_string::rbeginbasic_string::crbegin (C++11) basic_string::rendbasic_string::crend (C++11) Capacity basic_string::empty basic_string::sizebasic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (C++11)   Operations basic_string::clear basic_string::insert basic_string::erase basic_string::push_back basic_string::pop_back (C++11) basic_string::append basic_string::operator+= basic_string::compare basic_string::starts_with (C++20)   basic_string::ends_with (C++20) basic_string::contains (C++23) basic_string::replace basic_string::substr basic_string::copy basic_string::resize basic_string::resize_and_overwrite (C++23) basic_string::swap

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size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(until C++20)
constexpr size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(since C++20)

Copies a substring [pos, pos+count) to character string pointed to by dest. If the requested substring lasts past the end of the string, or if count == npos, the copied substring is [pos, size()). The resulting character string is not null-terminated.

If pos > size(), std::out_of_range is thrown.

Parameters

dest	-	pointer to the destination character string
count	-	length of the substring
pos	-	position of the first character to include

Return value

number of characters copied

Exceptions

std::out_of_range if pos > size().

Complexity

linear in count

Example

Run this code

#include <string>
#include <iostream>
 
int main()
{
  std::string foo("quuuux");
  char bar[7]{};
  foo.copy(bar, sizeof bar);
  std::cout << bar << '\n';
}

Output:

quuuux

See also

substr	returns a substring (public member function)
copy (C++17)	copies characters (public member function of std::basic_string_view<CharT,Traits>)
copycopy_if (C++11)	copies a range of elements to a new location (function template)
memcpy	copies one buffer to another (function)