dirfd(3)

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

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

44       For  an  explanation  of  the  terms  used   in   this   section,   see
45       attributes(7).
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47       ┌──────────┬───────────────┬─────────┐
48       │Interface │ Attribute     │ Value   │
49       ├──────────┼───────────────┼─────────┤
50       │dirfd()   │ Thread safety │ MT-Safe │
51       └──────────┴───────────────┴─────────┘

CONFORMING TO

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

61       This  page  is  part of release 4.15 of the Linux man-pages project.  A
62       description of the project, information about reporting bugs,  and  the
63       latest     version     of     this    page,    can    be    found    at
64       https://www.kernel.org/doc/man-pages/.
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68Linux                             2016-03-15                          DIRFD(3)