Get/set the string content.
  The first syntax returns a copy of the string content of the internal character sequence.
  The second syntax sets a copy of parameter s as the new internal character sequence (string).

Parameters.

s

string object whose content has to be copied into the streambuf.

Return Value.
  The second syntax returns an STL string object with a copy of the string content currently stored in the streambuf.

Example.

// stringbuf::str
#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main () {

  stringbuf sb;
  string mystr;

  sb.sputn ("Sample string",13);
  mystr=sb.str();

  cout << mystr;

  return 0;
}

Basic template member declaration ( basic_stringbuf<charT,traits,Allocator> ):

basic_string<charT,traits,Allocator> str () const; void str (const basic_string<charT,traits,Allocator> & s );

See also.
  stringbuf class