std::basic_streambuf<CharT, Traits>* rdbuf() const;
std::basic_streambuf<CharT, Traits>* rdbuf( std::basic_streambuf<CharT, Traits>* sb );

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.


sb - stream buffer to associate to

Return value

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


May throw implementation-defined exceptions.


#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
    // you will see this message
    std::cout << "back to default buffer\n";
    // print 'local' content
    std::cout << "local content: " << local.str() << "\n";


back to default buffer
local content: some message

See also

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

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