---
name: "acl_set_fd"
section: "3"
platform: "linux"
package: "acl"
version: "2.4.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/acl_set_fd"
---

# acl\_set\_fd(3)

set an ACL by file descriptor

## NAME

**acl\_set\_fd** – set an ACL by file descriptor

## LIBRARY

Linux Access Control Lists library (libacl, -lacl).

## SYNOPSIS

**#include \<sys/types.h\>**

**#include \<sys/acl.h\>**

*int*\

**acl\_set\_fd**(*int fd*, *acl\_t acl*);

## DESCRIPTION

The **acl\_set\_fd**() function associates an access ACL with the file referred to by *fd*.

The effective user ID of the process must match the owner of the file or the process must have the CAP\_FOWNER capability for the request to succeed.

## RETURN VALUE

The **acl\_set\_fd()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## ERRORS

If any of the following conditions occur, the **acl\_set\_fd**() function returns the value -1 and and sets *errno* to the corresponding value:

- \[EBADF\]

  The *fd* argument is not a valid file descriptor.

- \[EINVAL\]

  The argument *acl* does not point to a valid ACL.

  The ACL has more entries than the file referred to by *fd* can obtain.

- \[ENOSPC\]

  The directory or file system that would contain the new ACL cannot be extended or the file system is out of file allocation resources.

- \[ENOTSUP\]

  The file identified by *fd* cannot be associated with the ACL because the file system on which the file is located does not support this.

- \[EPERM\]

  The process does not have appropriate privilege to perform the operation to set the ACL.

- \[EROFS\]

  This function requires modification of a file system which is currently read-only.

## STANDARDS

IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)

## SEE ALSO

[acl\_delete\_def\_file(3)](/acl_delete_def_file/3.md), [acl\_get\_file(3)](/acl_get_file/3.md), [acl\_set\_file(3)](/acl_set_file/3.md), [acl\_valid(3)](/acl_valid/3.md), [acl(5)](/acl/5.md)

## AUTHOR

Derived from the FreeBSD manual pages written by Robert N M Watson ⟨rwatson@FreeBSD.org⟩, and adapted for Linux by Andreas Gruenbacher ⟨andreas.gruenbacher@gmail.com⟩.