1DIRFD(3)                   Linux Programmer's Manual                  DIRFD(3)
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NAME

6       dirfd - get directory stream file descriptor
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SYNOPSIS

9       #include <sys/types.h>
10       #include <dirent.h>
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12       int dirfd(DIR *dirp);
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14   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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16       dirfd():
17           /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L
18               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

21       The  function  dirfd()  returns the file descriptor associated with the
22       directory stream dirp.
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24       This file descriptor is  the  one  used  internally  by  the  directory
25       stream.   As  a  result,  it  is useful only for functions which do not
26       depend on or alter the file position, such as fstat(2)  and  fchdir(2).
27       It will be automatically closed when closedir(3) is called.
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RETURN VALUE

30       On  success, dirfd() returns a file descriptor (a nonnegative integer).
31       On error, -1 is returned, and errno is set to indicate the cause of the
32       error.
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ERRORS

35       POSIX.1-2008  specifies two errors, neither of which is returned by the
36       current implementation.
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38       EINVAL dirp does not refer to a valid directory stream.
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40       ENOTSUP
41              The implementation does not support the association  of  a  file
42              descriptor with a directory.
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ATTRIBUTES

45       For   an   explanation   of   the  terms  used  in  this  section,  see
46       attributes(7).
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48       ┌──────────┬───────────────┬─────────┐
49       │Interface │ Attribute     │ Value   │
50       ├──────────┼───────────────┼─────────┤
51       │dirfd()   │ Thread safety │ MT-Safe │
52       └──────────┴───────────────┴─────────┘

CONFORMING TO

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

58       open(2),  openat(2), closedir(3), opendir(3), readdir(3), rewinddir(3),
59       scandir(3), seekdir(3), telldir(3)
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COLOPHON

62       This page is part of release 5.07 of the Linux  man-pages  project.   A
63       description  of  the project, information about reporting bugs, and the
64       latest    version    of    this    page,    can     be     found     at
65       https://www.kernel.org/doc/man-pages/.
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69Linux                             2020-04-11                          DIRFD(3)
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