---
name: "dirfd"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/dirfd"
---

# dirfd(3)

get directory stream file descriptor

## NAME

dirfd - get directory stream file descriptor

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <sys/types.h>
#include <dirent.h>
```

**int dirfd(DIR \****dirp***);**

Feature Test Macro Requirements for glibc (see [**feature\_test\_macros**(7)](/feature_test_macros/7.md)):

**dirfd**():

```
    /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
```

## DESCRIPTION

The function **dirfd**() returns the file descriptor associated with the directory stream *dirp*.

This file descriptor is the one used internally by the directory stream. As a result, it is useful only for functions which do not depend on or alter the file position, such as [**fstat**(2)](/fstat/2.md) and [**fchdir**(2)](/fchdir/2.md). It will be automatically closed when [**closedir**(3)](/closedir/3.md) is called.

## RETURN VALUE

On success, **dirfd**() returns a file descriptor (a nonnegative integer). On error, -1 is returned, and *errno* is set to indicate the error.

## ERRORS

POSIX.1-2008 specifies two errors, neither of which is returned by the current implementation.

- **EINVAL**

  *dirp* does not refer to a valid directory stream.

- **ENOTSUP**

  The implementation does not support the association of a file descriptor with a directory.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **dirfd**() | Thread safety | MT-Safe |

## STANDARDS

POSIX.1-2008.

## HISTORY

4\.3BSD-Reno (not in 4.2BSD).

## SEE ALSO

[**open**(2)](/open/2.md), [**openat**(2)](/openat/2.md), [**closedir**(3)](/closedir/3.md), [**opendir**(3)](/opendir/3.md), [**readdir**(3)](/readdir/3.md), [**rewinddir**(3)](/rewinddir/3.md), [**scandir**(3)](/scandir/3.md), [**seekdir**(3)](/seekdir/3.md), [**telldir**(3)](/telldir/3.md)