Clears buffers for this stream and causes any buffered data to be written to the file, and also clears all intermediatefile buffers.
清除此流的缓冲区,将所有缓冲的数据都写入到文件中,另外也清除所有中间文件缓冲区。
3
One advantage of pipes on Linux and UNIX systems is that, unlike some other popular operating systems, there is no intermediatefile involved with a pipe.