c - 字符串使用的字符单元格数

Question

我有一个使用 UTF-8 字符串输出文本表的程序，我需要测量字符串使用的等宽字符单元格的数量，以便正确对齐它。如果可能的话，我想用标准函数来做到这一点。

Answer 1

来自 UTF-8 and Unicode FAQ for Unix/Linux :

The number of characters can be counted in C in a portable way using mbstowcs(NULL,s,0). This works for UTF-8 like for any other supported encoding, as long as the appropriate locale has been selected. A hard-wired technique to count the number of characters in a UTF-8 string is to count all bytes except those in the range 0x80 – 0xBF, because these are just continuation bytes and not characters of their own. However, the need to count characters arises surprisingly rarely in applications.