用c++程序编写猜单词游戏程序最后inline istream& Flush(istream& stream) { stream.clear(); int chars_to_skip = stream.rdbuf()->in_avail(); return stream.ignore(chars_to_skip); }是什么意思？

inline istream& Flush(istream& stream)

{
stream.clear();
int chars_to_skip = stream.rdbuf()->in_avail();
return stream.ignore(chars_to_skip);
}