opendir(3)

1opendir(3)                 Library Functions Manual                 opendir(3)
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NAME

6       opendir, fdopendir - open a directory
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

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

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

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

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

70       POSIX.1-2008.
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STANDARDS

73       opendir()
74              SVr4, 4.3BSD, POSIX.1-2001.
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76       fdopendir()
77              POSIX.1-2008.  glibc 2.4.
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NOTES

80       Filename entries can be read from a directory stream using readdir(3).
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82       The  underlying file descriptor of the directory stream can be obtained
83       using dirfd(3).
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85       The opendir()  function  sets  the  close-on-exec  flag  for  the  file
86       descriptor  underlying  the DIR *.  The fdopendir() function leaves the
87       setting of the close-on-exec flag unchanged for  the  file  descriptor,
88       fd.   POSIX.1-200x  leaves  it unspecified whether a successful call to
89       fdopendir() will set the close-on-exec flag for  the  file  descriptor,
90       fd.
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