advanced patterns with PHP's strpos when searching for substrings in UTF-8 encoded strings
I'm refactoring my project and I've spent hours debugging this and I'm working with an scenario when using the `strpos()` function in PHP 8.1 to find the position of a substring in a UTF-8 encoded string... Specifically, when trying to search for certain multibyte characters, `strpos()` is returning unexpected results. For example, I have the following code: ```php $haystack = 'γγγ«γ‘γ―δΈη'; // 'Hello World' in Japanese $needle = 'γ«γ‘'; $position = strpos($haystack, $needle); var_dump($position); ``` I expect `strpos()` to return `3`, since 'γ«γ‘' starts at the third character of the string. However, it returns `false`, which I assume indicates that the substring was not found. I have already ensured that the string is properly encoded in UTF-8. To troubleshoot, I've checked the encoding of both the haystack and the needle using `mb_detect_encoding()` and `mb_strlen()`, and both return expected results. I've also tried using `mb_strpos()` as suggested in some forums: ```php $position = mb_strpos($haystack, $needle, 0, 'UTF-8'); var_dump($position); ``` This returns `3` as expected, but I need to use `strpos()` for consistency in my application, which heavily relies on it for performance reasons. Is there something I'm missing with how `strpos()` handles UTF-8 strings? Are there best practices I should follow when dealing with multibyte strings in PHP, or should I just stick to `mb_*` functions for this use case? Any insight would be greatly appreciated! My team is using Php for this desktop app. Any help would be greatly appreciated!