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std::basic_ios::rdbuf

From cppreference.com
< cpp‎ | io‎ | basic ios
std::basic_streambuf<CharT, Traits>* rdbuf() const;
(1)
std::basic_streambuf<CharT, Traits>* rdbuf( std::basic_streambuf<CharT, Traits>* sb );
(2)

Manages the associated stream buffer.

1) Returns the associated stream buffer. If there is no associated stream buffer, returns a null pointer.
2) Sets the associated stream buffer to sb. The error state is cleared by calling clear(). Returns the associated stream buffer before the operation. If there is no associated stream buffer, returns a null pointer.

Contents

[edit] Parameters

sb - stream buffer to associate to

[edit] Return value

The associated stream buffer, or a null pointer if there was no associated stream buffer.

[edit] Exceptions

(none)

[edit] Example

#include <iostream>
#include <sstream>
 
int main()
{
    std::ostringstream local;
    auto cout_buff = std::cout.rdbuf(); // save pointer to std::cout buffer
 
    std::cout.rdbuf(local.rdbuf()); // substitute internal std::cout buffer with
        // buffer of 'local' object
 
    // now std::cout work with 'local' buffer
    // you don't see this message
    std::cout << "some message";
 
    // go back to old buffer
    std::cout.rdbuf(cout_buff);
 
    // you will see this message
    std::cout << "back to default buffer\n";
 
    // print 'local' content
    std::cout << "local content: " << local.str() << "\n";
}

Output:

back to default buffer
local content: some message

[edit] See also

replaces the rdbuf without clearing its error state
(protected member function) [edit]