dirfd - get directory stream file descriptor


   #include <sys/types.h>
   #include <dirent.h>

   int dirfd(DIR *dirp);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L
           || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


   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.


   On success, a nonnegative file descriptor is returned.  On error, -1 is
   returned, and errno is set to indicate the cause of the error.


   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.

          The  implementation  does  not support the association of a file
          descriptor with a directory.


   For  an  explanation  of  the  terms  used   in   this   section,   see

   Interface  Attribute      Value   
   dirfd()    Thread safety  MT-Safe 


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


   open(2), closedir(3), opendir(3), readdir(3), rewinddir(3), scandir(3),
   seekdir(3), telldir(3)


   This  page  is  part of release 4.09 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


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