:sig
s64 strpos(String haystack, String needle, s64 offset = 0)

:params
haystack : string to search in
needle : substring to search for
offset : optional start offset; negative values count from the end of the string
return value : zero-based position of the first match, or `-1` if `needle` is not found

:see
>string

:content
Finds the first occurrence of `needle` inside `haystack`.

This is the closest UCE equivalent to PHP `strpos()`, but it returns `-1` instead of `false` when no match is found.

If `needle` is an empty string, `strpos()` returns the normalized start offset.

Related:

- PHP: `strpos()`
- JavaScript / Node.js: `String.prototype.indexOf()`
