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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
       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 4.15 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                             2016-03-15                          DIRFD(3)