< cpp‎ | string‎ | basic string
const CharT* c_str() const;

Returns a pointer to a null-terminated character array with data equivalent to those stored in the string.

The pointer is such that the range [c_str(); c_str() + size()] is valid and the values in it correspond to the values stored in the string with an additional null character after the last position.

The pointer obtained from c_str() 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(), rbegin(), end() and rend().

Writing to the character array accessed through c_str() is undefined behavior.

c_str() and data() perform the same function. (since C++11)



Return value

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)




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


The pointer obtained from c_str() may only be treated as a pointer to a null-terminated character string if the string object does not contain other null characters.


#include <algorithm>
#include <cassert>
#include <cstring>
#include <string>
int main()
  std::string const s("Emplary");
  assert(s.size() == std::strlen(s.c_str()));
  assert(std::equal(s.begin(), s.end(), s.c_str()));
  assert(std::equal(s.c_str(), s.c_str() + s.size(), s.begin()));
  assert(0 == *(s.c_str() + s.size()));

See also

accesses the first character
(public member function)
accesses the last character
(public member function)
returns a pointer to the first character of a string
(public member function)