std::basic_stringbuf::str

 

C++

Language

Standard library headers

Concepts

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)

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated)

Streams

Abstractions

ios_base

basic_ios

basic_istream

basic_ostream

basic_iostream

File I/O

basic_ifstream

basic_ofstream

basic_fstream

String I/O

basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

istrstream (deprecated)

ostrstream (deprecated)

strstream (deprecated)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

std::basic_stringbuf

Public member functions

basic_stringbuf::basic_stringbuf

basic_stringbuf::operator= (C++11)

basic_stringbuf::swap (C++11)

basic_stringbuf::str

Protected member functions

basic_stringbuf::underflow

basic_stringbuf::pbackfail

basic_stringbuf::overflow

basic_stringbuf::setbuf

basic_stringbuf::seekoff

basic_stringbuf::seekpos

Non-member functions

swap(std::basic_stringbuf) (C++11)

 

std::basic_string<CharT, Traits, Allocator> str() const;	(1)
void str( const std::basic_string<CharT, Traits, Allocator>& s);	(2)

Gets and sets the underlying string.

1) Creates and returns a std::basic_string object containing a copy of this std::basic_stringbuf's underlying character sequence. For input-only streams, the returned string contains the characters from the range [eback(), egptr()). For input/output or output-only streams, contains the characters from pbase() to the last character in the sequence regardless of egptr() and epptr().

2) Deletes the entire underlying character sequence of this std::basic_stringbuf and then configures a new underlying character sequence containing a copy of the contents of s. The pointers of std::basic_streambuf are initialized as follows:

For input streams (mode & ios_base::in == true), eback() points at the first character, gptr() == eback(), and egptr() == eback() + s.size(): the subsequent input will read the first character copied from s.

For output streams (mode & ios_base::out == true), pbase() points at the first character and epptr() >= pbase() + s.size() (epptr is allowed to point farther so that the following sputc() wouldn't immediately call overflow())

For append streams (mode & ios_base::ate == true), pptr() == pbase() + s.size(), so that subsequent output will be appended to the last character copied from s (since C++11)

For no-appending output streams, pptr() == pbase(), so that subsequent output will overwrite the characters copied from s.

Parameters

s

-

a string object holding the replacement character sequence

Return value

1) A string object holding a copy of this buffer's underlying character sequence.

2) (none)

Notes

This function is typically accessed through std::basic_stringstream::str().

Example

run this code

#include <sstream>
#include <iostream>
int main()
{
    int n;
 
    std::istringstream in;  // could also use in("1 2")
    in.rdbuf()->str("1 2"); // set the get area
    in >> n;
    std::cout << "after reading the first int from \"1 2\", the int is " 
              << n << ", str() = \"" << in.rdbuf()->str() << "\"\n"; // or in.str()
 
    std::ostringstream out("1 2");
    out << 3;
    std::cout << "after writing the int '3' to output stream \"1 2\""
              << ", str() = \"" << out.str() << "\"\n";
 
    std::ostringstream ate("1 2", std::ios_base::ate); // C++11
    ate << 3;
    std::cout << "after writing the int '3' to append stream \"1 2\""
              << ", str() = \"" << ate.str() << "\"\n";
}

Output:

after reading the first int from "1 2", the int is 1, str() = "1 2"
after writing the int '3' to output stream "1 2", str() = "3 2"
after writing the int '3' to append stream "1 2", str() = "1 23"

See also

str	gets or sets the contents of underlying string device object (public member function of std::basic_stringstream)