Writes uncommitted changes to the underlying output sequence. Behaves as anUnformattedOutputFunction.

Ifrdbuf() is a null pointer, the sentry object is not constructed.

Otherwise, after constructing and checking the sentry object, callsrdbuf()->pubsync(). If the call returns-1, callssetstate(badbit).

[edit]Return value

*this

[edit]Exceptions

May throwstd::ios_base::failure if(exceptions()& badbit)!=0.

[edit]Example

#include <chrono>#include <iostream>#include <thread> usingnamespace std::chrono_literals; void f(){std::cout<<"Output from thread... ";for(int i{1}; i!=10;++i){std::this_thread::sleep_for(250ms);std::cout<< i<<' '; // output three numbers at once;// the effect is observable only in real-timeif(0==(i%3))std::cout.flush();}std::cout<<std::endl;// flushes as well} int main(){std::thread tr{f};std::this_thread::sleep_for(150ms);std::clog<<"Output from main\n";    tr.join();}

Output from mainOutput from thread... 1 2 3 4 5 6 7 8 9

[edit]Defect reports

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

[edit]See also

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