std::basic_string::data

const CharT* data() const;	(1)
CharT* data();	(2)	(since C++17)

Returns a pointer to the underlying array serving as character storage. The pointer is such that the range [data(); data() + size()) is valid and the values in it correspond to the values stored in the string.

The returned array is not required to be null-terminated. If empty() returns true, the pointer is a non-null pointer that should not be dereferenced.	(until C++11)
The returned array is null-terminated, that is, `data()` and c_str() perform the same function. If empty() returns true, the pointer points to a single null character.	(since C++11)

The pointer obtained from data() may be invalidated by:

Passing a non-const reference to the string to any standard library function, or
Calling non-const member functions on the string, excluding operator[](), at(), front(), back(), begin(), end(), rbegin(), rend().

1) Modifying the character array accessed through the const overload of data has undefined behavior.

2) Modifying the past-the-end null terminator stored at data()+size() has undefined behavior.

Parameters

(none)

Return value

A pointer to the underlying character storage.

data()[i] == operator[](i) for every `i` in `[0, size())`.	(until C++11)
data() + i == &operator[](i) for every `i` in `[0, size()]`.	(since C++11)

Complexity

Constant.

Exceptions

(none)	(until C++11)
`noexcept` specification: noexcept	(since C++11)

Example

Run this code

#include <algorithm>
#include <cassert>
#include <cstring>
#include <string>

int main()
{
  std::string const s("Emplary");
  assert(s.size() == std::strlen(s.data()));
  assert(std::equal(s.begin(), s.end(), s.data()));
  assert(std::equal(s.data(), s.data() + s.size(), s.begin()));
  assert(0 == *(s.data() + s.size()));
}

Language
Headers
Freestanding and hosted implementations
Named requirements
Language support library
Concepts library (C++20)
Diagnostics library
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

Null-terminated strings
Byte strings
Multibyte strings
Wide strings
Classes
basic_string
basic_string_view (C++17)
char_traits