# startPrank

Description: startPrank cheatcode documentation

Note: This document was authored using MDX

  Source: https://github.com/NomicFoundation/hardhat-website/tree/main/src/content/docs/docs/reference/cheatcodes/Environment/start-prank.mdx

  Components used in this page:
    - :::note: An informational callout block. Supports custom title `:::note[Title]` and icon `:::note{icon="name"}` syntax.

{/* This document contains content copied/adapted from the Foundry Book (MIT licensed). See LICENSE in the parent directory. */}

### Signature

```solidity
function startPrank(address msgSender) external;
```

```solidity
function startPrank(address msgSender, bool delegateCall) external;
```

```solidity
function startPrank(address msgSender, address txOrigin) external;
```

```solidity
function startPrank(
  address msgSender,
  address txOrigin,
  bool delegateCall
) external;
```

### Description

- `startPrank(address msgSender)`: sets `msg.sender` **for all subsequent calls** until [`stopPrank`](/docs/reference/cheatcodes/environment/stop-prank) is called.
- `startPrank(address msgSender, address txOrigin)`: sets `msg.sender` and `tx.origin` **for all subsequent calls** until [`stopPrank`](/docs/reference/cheatcodes/environment/stop-prank) is called.
- `startPrank(address msgSender, bool delegateCall)`: if `delegateCall` value is `true` then sets `msg.sender` **for all subsequent delegate calls** until [`stopPrank`](/docs/reference/cheatcodes/environment/stop-prank) is called.
- `startPrank(address msgSender, address txOrigin, bool delegateCall)`: if `delegateCall` value is `true` then sets `msg.sender` and `tx.origin` **for all subsequent delegate calls** until [`stopPrank`](/docs/reference/cheatcodes/environment/stop-prank) is called.

:::note
The delegate calls cannot be pranked from an EOA.
:::

### Examples

- prank delegate call and record state diffs

```solidity
contract ImplementationTest {
  uint public num;
  address public sender;

  function setNum(uint _num) public {
    num = _num;
  }
}

contract ProxyTest {
  uint public num;
  address public sender;
}

contract CheatcodesIssue is Script {
  function run() public {
    ProxyTest proxy = new ProxyTest();
    ImplementationTest impl = new ImplementationTest();

    vm.label(address(proxy), "proxy");
    vm.label(address(impl), "Impl");

    uint num = 42;
    vm.startPrank(address(proxy), true);
    vm.startStateDiffRecording();
    (bool successTwo, ) = address(impl).delegatecall(
      abi.encodeWithSignature("setNum(uint256)", num)
    );

    Vm.AccountAccess[] memory accountAccesses = vm.stopAndReturnStateDiff();
    console.log("accountAccesses.kind", uint8(accountAccesses[0].kind));
    console.log(
      "accountAccesses.accessor",
      vm.getLabel(accountAccesses[0].accessor)
    );
    console.log(
      "accountAccesses.account",
      vm.getLabel(accountAccesses[0].account)
    );
    console.logBytes(accountAccesses[0].data);
  }
}
```

```bash
== Logs ==
  accountAccesses.kind 1
  accountAccesses.accessor proxy
  accountAccesses.account Impl
  0xcd16ecbf000000000000000000000000000000000000000000000000000000000000002a
```

### SEE ALSO

Forge Standard Library

[`startHoax`](https://getfoundry.sh/reference/forge-std/startHoax), [`changePrank`](https://getfoundry.sh/reference/forge-std/change-prank)