使用串字符细胞的数目 [英] Number of character cells used by string

问题描述

我有一个程序，输出使用UTF-8字符串文本表，我需要测量所使用的一个字符串，所以我可以正确对齐等宽字符细胞的数量。如果可能的话，我想和标准功能做到这一点。

I have a program that outputs a textual table using UTF-8 strings, and I need to measure the number of monospaced character cells used by a string so I can align it properly. If possible, I'd like to do this with standard functions.

推荐答案

从的 UTF-8和统一code常见问题的Unix / Linux ：

字符数可以在C使用被计算在一个便携的方式 mbstowcs（NULL，S，0）。像其他任何支持的编码，只要相应的语言环境已选择本工程为UTF-8。硬连线技术，计算一个UTF-8字符串中的字符数是计算所有字节，除了那些在0x80的范围 - 为0xBF，因为这些都只是延续字节，而不是他们自己的角色。不过，需要数字符出奇很少出现在应用程序中。

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.

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