std::basic_ios::rdbuf

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< cpp‎ | io‎ | basic ios
 
C++
 
Input/output library
 
std::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 NULL.
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 NULL.

Parameters

sb - stream buffer to associate to

Return value

The associated stream buffer, or NULL if there was no associated stream buffer.

Exceptions

(none)

Example

Run this code
#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

See also

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