---
name: "io_uring_prep_waitid"
section: "3"
platform: "linux"
package: "liburing"
version: "2.15-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/io_uring_prep_waitid"
---

# io\_uring\_prep\_waitid(3)

prepare a waitid request

## NAME

io\_uring\_prep\_waitid - prepare a waitid request

## SYNOPSIS

```
#include <sys/wait.h>
#include <liburing.h>
```

**void io\_uring\_prep\_waitid(struct io\_uring\_sqe \****sqe***,**                           **idtype\_t** *idtype***,**                           **id\_t** *id***,**                           **siginfo\_t \****infop***,**                           **int** *options***,**                           **unsigned int** *flags***);**

## DESCRIPTION

The [**io\_uring\_prep\_waitid**(3)](/io_uring_prep_waitid/3.md) function prepares a waitid request. The submission queue entry *sqe* is setup to use the *idtype* and *id* arguments select the child(ren), and *options* to specify the child state changes to wait for. Upon successful return, it fills *infop* with information of the child process, if any. *flags* is io\_uring specific modifier flags. They are currently unused, and hence **0** should be passed.

This function prepares an async [**waitid**(2)](/waitid/2.md) request. See that man page for details.

Available since kernel 6.7.

## RETURN VALUE

None

## ERRORS

The CQE *res* field will contain the result of the operation. See the related man page for details on possible values. Note that where synchronous system calls will return **-1** on failure and set *errno* to the actual error value, io\_uring never uses *errno*. Instead it returns the negated *errno* directly in the CQE *res* field.

## SEE ALSO

[**io\_uring\_get\_sqe**(3)](/io_uring_get_sqe/3.md), [**io\_uring\_submit**(3)](/io_uring_submit/3.md), [**waitid**(2)](/waitid/2.md)