main/syscalls/timer_cancel.md

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# zx_timer_cancel

## Summary

Cancel a timer.

## Declaration

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

zx_status_t zx_timer_cancel(zx_handle_t handle);
```

## Description

`zx_timer_cancel()` cancels a pending timer that was started with
[`zx_timer_set()`].

Upon success the pending timer is canceled and the `ZX_TIMER_SIGNALED`
signal is de-asserted. If a new pending timer is immediately needed
rather than calling `zx_timer_cancel()` first, call [`zx_timer_set()`]
with the new deadline.

## Rights

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

## Return value

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

## Errors

`ZX_ERR_BAD_HANDLE`  *handle* is not a valid handle.

`ZX_ERR_ACCESS_DENIED`  *handle* lacks the right `ZX_RIGHT_WRITE`.

## NOTE

Calling this function before [`zx_timer_set()`] has no effect.

## See also

 - [`zx_timer_create()`]
 - [`zx_timer_set()`]

[`zx_timer_create()`]: timer_create.md
[`zx_timer_set()`]: timer_set.md