std::basic_stringbuf<CharT,Traits,Allocator>::setbuf

 

C++

Language

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Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

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Numerics library

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Regular expressions library (C++11)

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Technical Specifications

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated in C++98)

basic_syncbuf (C++20)

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 in C++98)

ostrstream (deprecated in C++98)

strstream (deprecated in C++98)

Synchronized Output

basic_osyncstream (C++20)

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)

 

protected: virtual std::basic_streambuf<CharT, Traits>* setbuf( char_type* s, std::streamsize n )

If s is a null pointer and n is zero, this function has no effect.

Otherwise, the effect is implementation-defined: some implementations do nothing, while some implementations clear the std::string member currently used as the buffer and begin using the user-supplied character array of size n, whose first element is pointed to by s, as the buffer and the input/output character sequence.

This function is protected virtual, it may only be called through pubsetbuf() or from member functions of a user-defined class derived from std::basic_stringbuf.

Parameters

s	-	pointer to the first CharT in the user-provided buffer or null
n	-	the number of CharT elements in the user-provided buffer or zero

Return value

this.

Notes

The deprecated stream buffer std::strstreambuf or the boost.IOStreams device boost::basic_array may be used to implement I/O buffering over a user-provided char array in portable manner.

Example

Test for the stringstream's setbuf functionality

Run this code

#include <iostream>
#include <sstream>
 
int main()
{
    std::ostringstream ss;
    char c[1024] = {};
    ss.rdbuf()->pubsetbuf(c, 1024);
    ss << 3.14 << '\n';
    std::cout << c << '\n';
}

Output:

3.14 (on GNU g++/libstdc++ and SunPro C++/roguewave)
<nothing> (on MS Visual Studio 2010, SunPro C++/stlport4, CLang++/libc++)

See also

pubsetbuf

invokes setbuf() (public member function of std::basic_streambuf<CharT,Traits>)