std::basic_streambuf<CharT,Traits>:: sputn, std::basic_streambuf<CharT,Traits>:: xsputn

If the put area becomes full ( pptr ( ) == epptr ( ) ), it is unspecified whether overflow() is actually called or its effect is achieved by other means.

Parameters

(none)

Return value

The number of characters successfully written.

Notes

"achieved by other means" permits bulk I/O without intermediate buffering: that is how std::ofstream::write() simply passes the pointer to the suitable system call in some implementations.

Example

#include <iostream>
#include <sstream>
 
int main()
{
    std::ostringstream s1;
    std::streamsize sz = s1.rdbuf()->sputn("This is a test", 14);
    s1 << '\n';
    std::cout << "The call to sputn() returned " << sz << '\n'
              << "The output sequence contains " << s1.str();
 
    std::istringstream s2;
    sz = s2.rdbuf()->sputn("This is a test", 14);
    std::cout << "The call to sputn() on an input stream returned " << sz << '\n';
}

The call to sputn() returned 14
The output sequence contains This is a test
The call to sputn() on an input stream returned 0

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also