## `makePersistent`

### Signature

```solidity
function makePersistent(address account) external;
function makePersistent(address account0, address account1) external;
function makePersistent(address account0, address account1, address account2) external;
function makePersistent(address[] calldata accounts) external;
```

### Description

Each fork has its own independent storage, which is replaced when another fork is selected. By default, only the test contract and `msg.sender` are persistent across forks.

Use `makePersistent` to mark additional accounts as persistent, meaning their state is available regardless of which fork is active.

### Parameters

| Parameter  | Type        | Description                           |
|------------|-------------|---------------------------------------|
| `account`  | `address`   | The account to mark as persistent     |
| `accounts` | `address[]` | Array of accounts to mark as persistent |

### Examples

```solidity [test/MakePersistent.t.sol]
function testMakePersistent() public {
    vm.selectFork(mainnetFork);
    
    // Deploy a contract on mainnet fork
    SimpleStorage simple = new SimpleStorage();
    simple.set(99);
    
    // Not persistent by default
    assertFalse(vm.isPersistent(address(simple)));
    
    // Mark as persistent
    vm.makePersistent(address(simple));
    assertTrue(vm.isPersistent(address(simple)));
    
    // Switch forks - contract state is preserved
    vm.selectFork(optimismFork);
    assertEq(simple.value(), 99);
}
```

### Gotchas

:::note
By default, only the test contract (`address(this)`) and the caller (`msg.sender`) are persistent across forks.
:::

### Related Cheatcodes

* [`isPersistent`](/reference/cheatcodes/is-persistent) - Check if an account is persistent
* [`revokePersistent`](/reference/cheatcodes/revoke-persistent) - Remove persistent status
* [`selectFork`](/reference/cheatcodes/select-fork) - Switch between forks