dirfd (3)

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dirfd - get directory stream file descriptor


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

int dirfd(DIR *dirp);

Feature Test Macro Requirements for glibc (see feature_test_macros(7) ):


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


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) and fchdir(2) . It will be automatically closed when closedir(3) 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 cause of the error.


POSIX.1-2008 specifies two errors, neither of which is returned by the current implementation.
dirp does not refer to a valid directory stream.
The implementation does not support the association of a file descriptor with a directory.


For an explanation of the terms used in this section, see attributes(7) .
dirfd() Thread safetyMT-Safe

Conforming to

POSIX.1-2008. This function was a BSD extension, present in 4.3BSD-Reno, not in 4.2BSD.

See Also

open(2) , openat(2) , closedir(3) , opendir(3) , readdir(3) , rewinddir(3) , scandir(3) , seekdir(3) , telldir(3)


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