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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 4.09 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
   https://www.kernel.org/doc/man-pages/.



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