:sig
String base64_decode(String raw, bool& ok)

:params
raw : Base64 encoded string
ok : set to `true` when decoding succeeds; set to `false` for invalid input
return value : decoded binary-safe string, or an empty string when decoding fails

:see
>string
base64_encode

:content
Decodes a Base64 string.

Pass a `bool` variable for `ok` so callers can distinguish invalid input from a valid empty decoded value.

Example:



:example
bool ok = false;
print(base64_decode("aGVsbG8=", ok), " ", ok ? "ok" : "bad", "\n");