home | help
std::fflush(3)		       C++ Standard Libary		  std::fflush(3)

NAME
     std::fflush - std::fflush

Synopsis
	Defined in header <cstdio>
	int fflush( std::FILE* stream );

	For  output  streams (and for update streams on which the last operation
     was output),
	writes any unwritten data from the stream's  buffer  to  the  associated
     output device.

	For  input  streams  (and for update streams on which the last operation
     was input),
	the behavior is undefined.

	If stream is a null pointer, all open output streams  are  flushed,  in-
     cluding the ones
	manipulated within library packages or otherwise not directly accessible
     to the
	program.

Parameters
	stream - the file stream to write out

Return value
	Returns zero on success. Otherwise EOF is returned and the error indica-
     tor of the
	file stream is set.

Notes
	POSIX  extends the specification of fflush by defining its effects on an
     input
	stream, as long as that stream represents a file or another seekable de-
     vice: in that
	case the POSIX file pointer  is  repositioned  to  match  the  C  stream
     pointer (which
	effectively   undoes   any  read  buffering)  and  the	effects  of  any
     std::ungetc or
	std::ungetwc that weren't yet read back from the stream are discarded.

	Microsoft also extends the specification of fflush by defining	its  ef-
     fects on an
	input  stream:	in  Visual Studio 2013 and prior, it discarded the input
     buffer, in
	Visual Studio 2015 and newer, it has no effect, buffers are retained.

See also
	fopen  opens a file
	       (function)
	fclose closes a file
	       (function)
	C documentation for
	fflush

http://cppreference.com 	   2024.06.10			  std::fflush(3)

home | help