RE: [PHP] substr and UTF-8

[snip] Actually this is false. I don't know what I was thinking. The high bit will be set in all bytes of a UTF-8 byte sequence. If it's not it's an ASCII character. The bytes are actually layed out as follows [1]: U-00000000 ___ U-0000007F: 0xxxxxxx U-00000080 ___ U-000007FF: 110xxxxx 10xxxxxx U-00000800 ___ U-0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx U-00010000 ___ U-001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx So there's no way to tell the last byte of a UTF-8 byte sequence but you can tell if it's the first byt looking at bits 7 and 8. Specifically, if bit 8 is not on, the character is ASCII and thus the "start" of a new character. Otherwise, if bit 7 is on it's the start of a new UTF-8 byte sequence. function is_utf8_start($b) { return (($b & 0x80) == 0) || ($b & 0x40); } [/snip] :) I think I will go with the mb_substr function, it works for me :)