main/syscalls/interrupt_ack.md

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# zx_interrupt_ack

## Summary

Acknowledge an interrupt and re-arm it.

## Declaration

```c
#include <zircon/syscalls.h>

zx_status_t zx_interrupt_ack(zx_handle_t handle);
```

## Description

`zx_interrupt_ack()` acknowledges a port-bound interrupt object which was previously
triggered, causing it to reset to the untriggered state and be eligible to trigger again,
delivering a packet to the port it is bound to in the process.

If the interrupt object is a physical level-triggered interrupt which is still asserted, or
is an edge or virtual interrupt that has been asserted since it was last triggered, the
interrupt will immediately trigger again delivering a packet to the port it is bound to.

This syscall only operates on interrupts bound to a port.  Interrupts being waited upon with
[`zx_interrupt_wait()`] cannot be re-armed with this call -- it happens automatically when
[`zx_interrupt_wait()`] is called again after a previous [`zx_interrupt_wait()`] operation
has been satisfied.  Please see (here)[Interrupts#asynchronous-waiting-and-acknowledgement]
for details on how to properly wait for and acknowledge interrupt events when using a
port-bound interrupt object.

## Rights

*handle* must be of type `ZX_OBJ_TYPE_INTERRUPT` and have `ZX_RIGHT_WRITE`.

## Return value

`zx_interrupt_ack()` returns `ZX_OK` on success. In the event
of failure, a negative error value is returned.

## Errors

`ZX_ERR_BAD_HANDLE` *handle* is an invalid handle.

`ZX_ERR_WRONG_TYPE` *handle* is not an interrupt object.

`ZX_ERR_BAD_STATE` *handle* is not bound to a port.

`ZX_ERR_CANCELED`  [`zx_interrupt_destroy()`] was called on *handle*.

`ZX_ERR_ACCESS_DENIED` *handle* lacks `ZX_RIGHT_WRITE`.

## See also

 - [Interrupts]
 - [`zx_handle_close()`]
 - [`zx_interrupt_bind()`]
 - [`zx_interrupt_create()`]
 - [`zx_interrupt_destroy()`]
 - [`zx_interrupt_trigger()`]
 - [`zx_interrupt_wait()`]
 - [`zx_port_wait()`]

[Interrupts]: /docs/reference/kernel_objects/interrupts.md
[Interrupts#asynchronous-waiting-and-acknowledgement]: /docs/reference/kernel_objects/interrupts.md#asynchronous-waiting-and-acknowledgement
[`zx_handle_close()`]: handle_close.md
[`zx_interrupt_bind()`]: interrupt_bind.md
[`zx_interrupt_create()`]: interrupt_create.md
[`zx_interrupt_destroy()`]: interrupt_destroy.md
[`zx_interrupt_trigger()`]: interrupt_trigger.md
[`zx_interrupt_wait()`]: interrupt_wait.md
[`zx_port_wait()`]: port_wait.md