---
name: "io_uring_prep_close"
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_close"
---

# io\_uring\_prep\_close(3)

prepare a file descriptor close request

## NAME

io\_uring\_prep\_close - prepare a file descriptor close request

## SYNOPSIS

```
#include <liburing.h>
```

**void io\_uring\_prep\_close(struct io\_uring\_sqe \****sqe***,**                           **int** *fd***);**

**void io\_uring\_prep\_close\_direct(struct io\_uring\_sqe \****sqe***,**                                 **unsigned** *file\_index***);**

## DESCRIPTION

The [**io\_uring\_prep\_close**(3)](/io_uring_prep_close/3.md) function prepares a close request. The submission queue entry *sqe* is setup to close the file descriptor indicated by *fd*.

For a direct descriptor close request, the offset is specified by the *file\_index* argument instead of the *fd*. This is identical to unregistering the direct descriptor, and is provided as a convenience. Note that even though it's closing a direct descriptor, the application must not set **IOSQE\_FIXED\_FILE** on the SQE. Otherwise the request will complete with **-EBADF** as the result.

These functions prepare an async [**close**(2)](/close/2.md) request. See that man page for details.

## 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. For closing of a direct descriptor, the only failure cases are the kernel running completely out of memory, or if the application has specified an invalid direct descriptor. 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), [**close**(2)](/close/2.md)