---
name: "acl_cmp"
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_cmp"
---

# acl\_cmp(3)

compare two ACLs

## NAME

**acl\_cmp** – compare two ACLs

## LIBRARY

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

## SYNOPSIS

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

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

*int*\

**acl\_cmp**(*acl\_t acl1*, *acl\_t acl2*);

## DESCRIPTION

The **acl\_cmp**() function compares the ACLs pointed to by the arguments *acl1* and *acl2* for equality. The two ACLs are considered equal if for each entry in *acl1* there is an entry in *acl2* with matching tag type, qualifier, and permissions, and vice versa.

## RETURN VALUE

If successful, the **acl\_cmp**() function returns 0 if the two ACLs *acl1* and *acl2* are equal, and 1 if they differ. 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\_cmp**() function returns -1 and sets *errno* to the corresponding value:

- \[EINVAL\]

  The argument *acl1* is not a valid pointer to an ACL.

  The argument *acl2* is not a valid pointer to an ACL.

## STANDARDS

This is a non-portable, Linux specific extension to the ACL manipulation functions defined in IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned).

## SEE ALSO

[acl(5)](/acl/5.md)

## AUTHOR

Written by Andreas Gruenbacher ⟨andreas.gruenbacher@gmail.com⟩.