Function CSTL_u8string_replace_n_at

pub unsafe extern "C" fn CSTL_u8string_replace_n_at(
    instance: CSTL_UTF8StringRef,
    off: usize,
    count: usize,
    ptr: *const char8_t,
    count2: usize,
    alloc: *mut CSTL_Alloc,
) -> bool

Replaces the substring at offset off in instance with the length given by count with the first count2 characters of the string at ptr.

If off is outside of the range [instance, instance + CSTL_u8string_size(instance)] or if the length of the resulting string is greater than CSTL_u8string_max_size() this function has no effect and returns false, otherwise it returns true.