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 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, a nonnegative file descriptor is returned. 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 attributes(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), closedir(3), opendir(3), readdir(3), rewinddir(3), scandir(3), seekdir(3), telldir(3)
Colophon
This page is part of release 5.04 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/.
Referenced By
opendir(3), perl5220delta(1), perlfunc(1), readdir(3).