utf8Strlen

fnglong utf8Strlen(string p, ptrdiff_t max)

Computes the length of the string in characters, not including the terminating nul character. If the max'th byte falls in the middle of a character, the last (partial) character is not counted.

Parameters

`p`	pointer to the start of a UTF-8 encoded string
`max`	the maximum number of bytes to examine. If max is less than 0, then the string is assumed to be nul-terminated. If max is 0, `p` will not be examined and may be null. If max is greater than 0, up to max bytes are examined

Returns

the length of the string in characters