---
name: "rtapi_task_start"
section: "3rtapi"
platform: "linux"
package: "linuxcnc-uspace-dev"
version: "1:2.9.4-2+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/rtapi_task_start"
---

# rtapi\_task\_start(3rtapi)

start a realtime task in periodic mode

## NAME

rtapi\_task\_start - start a realtime task in periodic mode

## SYNTAX

int rtapi\_task\_start(int *task\_id*, unsigned long *period\_nsec*)

## ARGUMENTS

- *task\_id*

  A task ID returned by a previous call to **rtapi\_task\_new**

- *period\_nsec*

  The clock period in nanoseconds between iterations of a periodic task

## DESCRIPTION

**rtapi\_task\_start** starts a task in periodic mode.  The task must be in the *paused* state.

## REALTIME CONSIDERATIONS

Call only from within init/cleanup code, not from realtime tasks.

## RETURN VALUE

Returns an RTAPI status code.

## SEE ALSO

**[rtapi\_task\_new(3rtapi)](/rtapi_task_new/3rtapi.md)**, **[rtapi\_task\_pause(3rtapi)](/rtapi_task_pause/3rtapi.md)**, **[rtapi\_task\_resume(3rtapi)](/rtapi_task_resume/3rtapi.md)**