---
title: rollback
---
import { Aside, Tabs, TabItem, LinkButton } from '@astrojs/starlight/components';

### Concepts

<LinkButton href="/docs/hooks/concepts/introduction/">Introduction</LinkButton>
<LinkButton href="/docs/hooks/concepts/execution-metadata/">Execution Metadata</LinkButton>

### Behaviour

End the execution of the hook with status: reject.

* Record a return string and return code in transaction metadata.
* Discard all state changes.
* Discard all `emit()` transactions.
* Disallow originating transaction to continue.

<Aside type="caution">
  The originating transaction will fail with <code>tecHOOK_REJECTED</code> and a fee will be charged. See: Execution Order.
</Aside>

### Definition

<Tabs>
<TabItem label="C">
```c
int64_t rollback (
    uint32_t read_ptr,
    uint32_t read_len,
    uint64_t error_code
);
```
</TabItem>
<TabItem label="JavaScript">
```javascript
function rollback(error_msg: string, error_code: number): number
```
</TabItem>
</Tabs>

### Example

<Tabs>
<TabItem label="C">
```c
rollback("Rejected!", 9, 100);
```
</TabItem>
<TabItem label="JavaScript">
```javascript
rollback('Rejected!', 100)
```
</TabItem>
</Tabs>

### Parameters

<Tabs>
<TabItem label="C">

<table><thead><tr><th>Name</th><th>Type</th><th width="202">Description</th></tr></thead><tbody><tr><td>read_ptr</td><td>uint32_t</td><td>Pointer to a return string to be stored in execution metadata.<br />This is any string the hook-developer wishes to return with the acceptance. <em>May be null.</em></td></tr><tr><td>read_len</td><td>uint32_t</td><td>The length of the return string. At most 32. <em>May be null.</em></td></tr><tr><td>error_code</td><td>uint64_t</td><td>A return code specific to this hook to be stored in execution metadata.<br /><br />Similar to the return code of an application on a *nix system. By convention non-success is non-zero.</td></tr></tbody></table>
</TabItem>
<TabItem label="JavaScript">

<table><thead><tr><th>Name</th><th>Type</th><th width="202">Description</th></tr></thead><tbody><tr><td>error_msg</td><td>string</td><td>String to be stored in execution metadata.<br />This is any string the hook-developer wishes to return with the acceptance. <em>May be null.</em></td></tr><tr><td>error_code</td><td>number</td><td>A return code specific to this hook to be stored in execution metadata.<br /><br />Similar to the return code of an application on a *nix system. By convention non-success is non-zero.</td></tr></tbody></table>
</TabItem>
</Tabs>

### Return Code

<Tabs>
<TabItem label="C">
<table><thead><tr><th width="123">Type</th><th>Description</th></tr></thead><tbody><tr><td>int64_t</td><td>Rollback ends the hook, therefore no value is returned to the caller. By convention all Hook APIs return <code>int64_t</code>, but in this case nothing is returned.</td></tr></tbody></table>
</TabItem>
<TabItem label="JavaScript">
<table><thead><tr><th width="123">Type</th><th>Description</th></tr></thead><tbody><tr><td>number</td><td>Rollback ends the hook, therefore no value is returned to the caller. By convention all Hook APIs return <code>number</code>, but in this case nothing is returned.</td></tr></tbody></table>
</TabItem>
</Tabs>
