For these functions, a printable character is a character with a visible representation;whitespace is one of space, tab, vertical tab, return, newline, and formfeed;

• 表中的这些函数，可打印的字符是指那些可以表示的字符，空白字符则是空格、制表符、垂直制表符、回车符、换行符和进纸符中的任意一种；