std::basic_ostream::flush
From cppreference.com
< cpp | io | basic ostream
| 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).
Parameters
(none)
Return value
*this
Exceptions
May throw std::ios_base::failure if exceptions()&badbit!=0.
Example
Run this code
#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) | |
| flushes the output stream (function template) | |
| outputs '\n' and flushes the output stream (function template) |