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():
           _BSD_SOURCE || _SVID_SOURCE
           || /* Since glibc 2.10: */
               (_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)

DESCRIPTION
       The  function  dirfd()  returns  the  file descriptor associated with the directory stream
       dirp.

       This 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 implementa‐
       tion.

       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
   Multithreading (see pthreads(7))
       The dirfd() function is thread-safe.

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

NOTES
       The prototype for dirfd() is available only if _BSD_SOURCE or _SVID_SOURCE is defined.

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 3.74 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 http://www.kernel.org/doc/man-pages/.



Linux                                       2013-07-05                                   DIRFD(3)