---
name: "rte_eal_alarm_cancel"
section: "3"
platform: "linux"
package: "dpdk-doc"
version: "24.11.4-0+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/rte_alarm.h"
---

# rte\_eal\_alarm\_cancel(3)

Part of [rte\_alarm.h(3)](/rte_alarm.h/3.md).

## NAME

rte\_alarm.h

## SYNOPSIS

`#include <stdint.h>`\

### Typedefs

**typedef** void(\* **rte\_eal\_alarm\_callback**) (void \*arg)\

### Functions

int **rte\_eal\_alarm\_set** (uint64\_t us, **rte\_eal\_alarm\_callback** cb, void \*cb\_arg)\
 int **rte\_eal\_alarm\_cancel** (**rte\_eal\_alarm\_callback** cb\_fn, void \*cb\_arg)\

## Detailed Description

Alarm functions

Simple alarm-clock functionality supplied by eal. Does not require hpet support.

Definition in file **rte\_alarm.h**.

## Typedef Documentation

### typedef void(\* rte\_eal\_alarm\_callback) (void \*arg)

Signature of callback back function called when an alarm goes off.

Definition at line **26** of file **rte\_alarm.h**.

## Function Documentation

### int rte\_eal\_alarm\_set (uint64\_t us, rte\_eal\_alarm\_callback cb, void \* cb\_arg)

Function to set a callback to be triggered when us microseconds have expired. Accuracy of timing to the microsecond is not guaranteed. The alarm function will not be called *before* the requested time, but may be called a short period of time afterwards. The alarm handler will be called only once. There is no need to call 'rte\_eal\_alarm\_cancel' from within the callback function.

**Parameters**

*us* The time in microseconds before the callback is called \
 *cb* The function to be called when the alarm expires \
 *cb\_arg* Pointer parameter to be passed to the callback function

**Returns**

On success, zero. On failure, a negative error number

### int rte\_eal\_alarm\_cancel (rte\_eal\_alarm\_callback cb\_fn, void \* cb\_arg)

Function to cancel an alarm callback which has been registered before. If used outside alarm callback it wait for all callbacks to finish execution.

**Parameters**

*cb\_fn* alarm callback \
 *cb\_arg* Pointer parameter to be passed to the callback function. To remove all copies of a given callback function, irrespective of parameter, (void \*)-1 can be used here.

**Returns**

- •

  value greater than 0 and rte\_errno not changed - returned value is the number of canceled alarm callback functions

- •

  value greater or equal 0 and rte\_errno set to EINPROGRESS, at least one alarm could not be canceled because cancellation was requested from alarm callback context. Returned value is the number of successfully canceled alarm callbacks

- •

  0 and rte\_errno set to ENOENT - no alarm found

- •

  \-1 and rte\_errno set to EINVAL - invalid parameter (NULL callback)

## Author

Generated automatically by Doxygen for DPDK from the source code.