public member function

std::string::data

const char* data() const;

const char* data() const noexcept;

Get string data

Returns a pointer to an array that contains the same sequence of characters as the characters that make up the value of the string object.

Accessing the value at

data()+size()

produces undefined behavior: There are no guarantees that a null character terminates the character sequence pointed by the value returned by this function. See string::c_str for a function that provides such guarantee.

A program shall not alter any of the characters in this sequence.

Returns a pointer to an array that contains a null-terminated sequence of characters (i.e., a C-string) representing the current value of the string object.

This array includes the same sequence of characters that make up the value of the string object plus an additional terminating null-character (

'\0'

) at the end.

The pointer returned points to the internal array currently used by the string object to store the characters that conform its value.

Both

string::data

and string::c_str are synonyms and return the same value.

The pointer returned may be invalidated by further calls to other member functions that modify the object.

Parameters

none

Return Value

A pointer to the c-string representation of the string object's value.

Example

// string::data
#include <iostream>
#include <string>
#include <cstring>

int main ()
{
  int length;

  std::string str = "Test string";
  char* cstr = "Test string";

  if ( str.length() == std::strlen(cstr) )
  {
    std::cout << "str and cstr have the same length.\n";

    if ( memcmp (cstr, str.data(), str.length() ) == 0 )
      std::cout << "str and cstr have the same content.\n";
  }
  return 0;
}

Output:

str and cstr have the same length.
str and cstr have the same content.

Complexity, iterator, access, exceptions

Unspecified or contradictory specifications.

Complexity

Constant.

Iterator validity

No changes.

Data races

The object is accessed.

Exception safety

No-throw guarantee: this member function never throws exceptions.