---
name: "fdopendir"
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/opendir"
---

# fdopendir(3)

open a directory

Part of [opendir(3)](/opendir/3.md).

## NAME

opendir, fdopendir - open a directory

## LIBRARY

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

## SYNOPSIS

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

**DIR \*opendir(const char \****name***);** **DIR \*fdopendir(int** *fd***);**

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

**fdopendir**():

```
    Since glibc 2.10:
        _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:
        _GNU_SOURCE
```

## DESCRIPTION

The **opendir**() function opens a directory stream corresponding to the directory *name*, and returns a pointer to the directory stream. The stream is positioned at the first entry in the directory.

The **fdopendir**() function is like **opendir**(), but returns a directory stream for the directory referred to by the open file descriptor *fd*. After a successful call to **fdopendir**(), *fd* is used internally by the implementation, and should not otherwise be used by the application.

## RETURN VALUE

The **opendir**() and **fdopendir**() functions return a pointer to the directory stream. On error, NULL is returned, and *errno* is set to indicate the error.

## ERRORS

- **EACCES**

  Permission denied.

- **EBADF**

  *fd* is not a valid file descriptor opened for reading.

- **EMFILE**

  The per-process limit on the number of open file descriptors has been reached.

- **ENAMETOOLONG**

  *name* was too long.

- **ENFILE**

  The system-wide limit on the total number of open files has been reached.

- **ENOENT**

  Directory does not exist, or *name* is an empty string.

- **ENOMEM**

  Insufficient memory to complete the operation.

- **ENOTDIR**

  *name* is not a directory.

## ATTRIBUTES

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

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **opendir**(), **fdopendir**() | Thread safety | MT-Safe |

## STANDARDS

POSIX.1-2008.

## STANDARDS

- **opendir**()

  SVr4, 4.3BSD, POSIX.1-2001.

- **fdopendir**()

  POSIX.1-2008. glibc 2.4.

## NOTES

Filename entries can be read from a directory stream using [**readdir**(3)](/readdir/3.md).

The underlying file descriptor of the directory stream can be obtained using [**dirfd**(3)](/dirfd/3.md).

The **opendir**() function sets the close-on-exec flag for the file descriptor underlying the *DIR \**. The **fdopendir**() function leaves the setting of the close-on-exec flag unchanged for the file descriptor, *fd*. POSIX.1-200x leaves it unspecified whether a successful call to **fdopendir**() will set the close-on-exec flag for the file descriptor, *fd*.

## SEE ALSO

[**open**(2)](/open/2.md), [**closedir**(3)](/closedir/3.md), [**dirfd**(3)](/dirfd/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)