dirfd(3)                   Library Functions Manual                   dirfd(3)

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)):

       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) 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 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 |
       +--------------------------------------------+---------------+---------+
STANDARDS
       POSIX.1-2008.

HISTORY
       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)

Linux man-pages 6.7               2023-10-31                          dirfd(3)