NAME

std::basic_string::data - std::basic_string::data

Synopsis

const CharT* data() const; (until C++11)
const CharT* data() const noexcept; (since C++11)
(until C++20)
constexpr const CharT* data() const noexcept; (1) (since C++20)
CharT* data() noexcept; (since C++17)
(2) (until C++20)
constexpr CharT* data() noexcept; (since C++20)

Returns a pointer to the underlying array serving as character storage. The pointer
is such that the range

[data(); data() + size())
(until C++11)
[data(); data() + size()]
(since C++11)

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

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() to any value
other than CharT() 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 == std::addressof(operator[](i)) for every i in [0, (since C++11)
size()].

Complexity

Constant.

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()));
}

See also

front accesses the first character
(C++11) (public member function)
back accesses the last character
(C++11) (public member function)
c_str returns a non-modifiable standard C character array version of the string
(public member function)
data returns a pointer to the first character of a view
(C++17) (public member function of std::basic_string_view<CharT,Traits>)