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

> function extract_ operation_ arg(gtx_ transaction: gtx_ transaction, op_ name: text, arg: integer, verify_ signers: boolean, require_ anchored_ proof: bool

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.iccf/extract_operation_arg/

FUNCTION

# extract\_operation\_arg

```signature
function extract_operation_arg(gtx_transaction: gtx_transaction, op_name: text, arg: integer, verify_signers: boolean, require_anchored_proof: boolean, min_timestamp: integer, max_timestamp: integer, valid_source_blockchain_rids: set<byte_array>?): gtv
```

[Source](https://gitlab.com/chromaway/ft4-lib/src/development/rell/src/lib/iccf/module.rell#lines-45)

Requires the presented transaction to be proved and extracts an argument from the specified operation

**Parameters**

* **gtx\_transaction** — The transaction to verify
* **op\_name** — Name of the operation to extract
* **arg** — Index of the argument to be extracted (default: first argument)
* **verify\_signers** — Whether or not the signers must match current transaction signatures
* **require\_anchored\_proof** — Whether or not we require inclusion of a proof that the block containing the transaction has been anchored in cluster anchoring chain
* **min\_timestamp** — Limit for how old the transaction is allowed to be, disabled if 0
* **max\_timestamp** — Limit for how new the transaction is allowed to be, disabled if 0
* **valid\_source\_blockchain\_rids** — Valid source blockchains for transaction

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