Function CSTL_string_find_str

pub unsafe extern "C" fn CSTL_string_find_str(
    instance: CSTL_StringCRef,
    other: CSTL_StringCRef,
    off: usize,
) -> usize

Find the first from offset off substring equal to the string other and return its position from the start of the original string.

If no match is found CSTL_string_npos is returned.