# extract_account_id · FT4 Rell API · Chromia Docs (concept)

> function extract_ account_ id(auth_ op: gtx_ operation): byte_ array Extracts the account ID passed to the auth operation, which is any operation supported

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.auth/extract_account_id/

FUNCTION

# extract\_account\_id

```signature
function extract_account_id(auth_op: gtx_operation): byte_array
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/auth/authentication.rell#lines-765)

Extracts the account ID passed to the auth operation, which is any operation supported by
`is_auth_op`.

Throws `"INVALID AUTH OP"` if the operation passed is not an auth operation

Throws `"INVALID AUTH ARGS"` if the auth operation passed has no arguments

**Parameters**

* **auth\_op** — the operation to extract the ID from

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.auth/extract_account_id.html)Generated API reference, mirrored from the live docs