opendir(3)

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

6       opendir, fdopendir - open a directory
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SYNOPSIS

9       #include <sys/types.h>
10       #include <dirent.h>
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12       DIR *opendir(const char *name);
13       DIR *fdopendir(int fd);
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15   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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17       fdopendir():
18           Since glibc 2.10:
19               _POSIX_C_SOURCE >= 200809L
20           Before glibc 2.10:
21               _GNU_SOURCE
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DESCRIPTION

24       The  opendir()  function  opens a directory stream corresponding to the
25       directory name, and returns a pointer to  the  directory  stream.   The
26       stream is positioned at the first entry in the directory.
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28       The  fdopendir()  function  is  like opendir(), but returns a directory
29       stream for the directory referred to by the open  file  descriptor  fd.
30       After  a  successful  call to fdopendir(), fd is used internally by the
31       implementation, and should not otherwise be used by the application.
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RETURN VALUE

34       The opendir() and fdopendir() functions return a pointer to the  direc‐
35       tory  stream.  On error, NULL is returned, and errno is set to indicate
36       the error.
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ERRORS

39       EACCES Permission denied.
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41       EBADF  fd is not a valid file descriptor opened for reading.
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43       EMFILE The per-process limit on the number of open file descriptors has
44              been reached.
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46       ENFILE The system-wide limit on the total number of open files has been
47              reached.
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49       ENOENT Directory does not exist, or name is an empty string.
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51       ENOMEM Insufficient memory to complete the operation.
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53       ENOTDIR
54              name is not a directory.
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VERSIONS

57       fdopendir() is available in glibc since version 2.4.
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ATTRIBUTES

60       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
61       tributes(7).
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63       ┌────────────────────────────────────────────┬───────────────┬─────────┐
64       │Interface                                   │ Attribute     │ Value   │
65       ├────────────────────────────────────────────┼───────────────┼─────────┤
66       │opendir(), fdopendir()                      │ Thread safety │ MT-Safe │
67       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

70       opendir()  is  present  on SVr4, 4.3BSD, and specified in POSIX.1-2001.
71       fdopendir() is specified in POSIX.1-2008.
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NOTES

74       Filename entries can be read from a directory stream using readdir(3).
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76       The underlying file descriptor of the directory stream can be  obtained
77       using dirfd(3).
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79       The  opendir()  function  sets  the close-on-exec flag for the file de‐
80       scriptor underlying the DIR *.  The  fdopendir()  function  leaves  the
81       setting  of  the  close-on-exec flag unchanged for the file descriptor,
82       fd.  POSIX.1-200x leaves it unspecified whether a  successful  call  to
83       fdopendir()  will  set  the close-on-exec flag for the file descriptor,
84       fd.
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COLOPHON

91       This  page  is  part of release 5.12 of the Linux man-pages project.  A
92       description of the project, information about reporting bugs,  and  the
93       latest     version     of     this    page,    can    be    found    at
94       https://www.kernel.org/doc/man-pages/.
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98GNU                               2021-03-22                        OPENDIR(3)