std::flush
| Defined in header <ostream>
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| template< class CharT, class Traits > std::basic_ostream<CharT, Traits>& flush( std::basic_ostream<CharT, Traits>& os ); |
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Flushes the output sequence os as if by calling os.flush().
This is an output-only I/O manipulator, it may be called with an expression such as out << std::flush for any out of type std::basic_ostream.
Notes
This manipulator may be used to produce an incomplete line of output immediately, e.g. when displaying output from a long-running process, logging activity of multiple threads or logging activity of a program that may crash unexpectedly. An explicit flush of std::cout is also necessary before a call to std::system, if the spawned process performs any screen I/O (a common example is std::system("pause") on Windows). In most other usual interactive I/O scenarios, std::endl is redundant when used with std::cout because any input from std::cin, output to std::cerr, or program termination forces a call to std::cout.flush().
When a complete line of output needs to be flushed, the std::endl manipulator may be used.
When every output operation needs to be flushed, the std::unitbuf manipulator may be used.
Parameters
| os | - | reference to output stream |
Return value
os (reference to the stream after manipulation)