DIRFD(3) Linux Programmer's Manual DIRFD(3)
NAME
dirfd - get directory stream file descriptor
SYNOPSIS
#include <sys/types.h>
#include <dirent.h>
int dirfd(DIR *dirp);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
dirfd():
/* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L
|| /* Glibc versions <= 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 de-
pend 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.
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 at-
tributes(7).
┌──────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────┼───────────────┼─────────┤
│dirfd() │ Thread safety │ MT-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)
COLOPHON
This page is part of release 5.10 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2020-04-11 DIRFD(3)
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