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std::basic_ostream::flush

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< cpp‎ | io‎ | basic ostream
Revision as of 22:58, 31 May 2013 by P12bot (Talk | contribs)

basic_ostream& flush();


Writes uncommitted changes to the underlying output sequence.

If rdbuf() is a null pointer, does nothing

Otherwise, behaves as an UnformattedOutputFunction (since C++11). After constructing and checking the sentry object, calls rdbuf()->pubsync(). If the call returns -1, calls setstate(badbit).

Contents

Parameters

(none)

Return value

*this

Exceptions

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

Example

#include <thread>
#include <iostream>
#include <chrono>
void f()
{
    std::cout << "Output from thread...";
    std::this_thread::sleep_for(std::chrono::seconds(2));
    std::cout << "...thread calls flush()\n";
    std::cout.flush();
}
 
int main()
{
    std::thread t1(f);
    std::this_thread::sleep_for(std::chrono::seconds(1));
    std::clog << "Output from main\n";
    t1.join();
}

Output:

Output from main
Output from thread.....thread calls flush()

See also

synchronizes with the underlying storage device
(public member function of std::basic_istream) [edit]
flushes the output stream
(function template)
outputs '\n' and flushes the output stream
(function template)