man3/opendir.3

   1 .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
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  12 .\" Since the Linux kernel and libraries are constantly changing, this
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  22 .\"
  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Sat Jul 24 18:46:01 1993 by Rik Faith (faith@cs.unc.edu)
  28 .\" Modified 11 June 1995 by Andries Brouwer (aeb@cwi.nl)
  29 .\" 2007-07-30 Ulrich Drepper <drepper@redhat.com>: document fdopendir().
  30 .TH OPENDIR 3  2010-06-20 "GNU" "Linux Programmer's Manual"
  31 .SH NAME
  32 opendir, fdopendir \- open a directory
  33 .SH SYNOPSIS
  34 .nf
  35 .B #include <sys/types.h>
  36 .br
  37 .B #include <dirent.h>
  38 .sp
  39 .BI "DIR *opendir(const char *" name );
  40 .BI "DIR *fdopendir(int " fd );
  41 .fi
  42 .sp
  43 .in -4n
  44 Feature Test Macro Requirements for glibc (see
  45 .BR feature_test_macros (7)):
  46 .in
  47 .sp
  48 .BR fdopendir ():
  49 .PD 0
  50 .ad l
  51 .RS 4
  52 .TP 4
  53 Since glibc 2.10:
  54 _XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
  55 .TP
  56 Before glibc 2.10:
  57 _GNU_SOURCE
  58 .RE
  59 .ad
  60 .PD
  61 .SH DESCRIPTION
  62 The
  63 .BR opendir ()
  64 function opens a directory stream corresponding to the
  65 directory \fIname\fP, and returns a pointer to the directory stream.
  66 The stream is positioned at the first entry in the directory.
  67
  68 The
  69 .BR fdopendir ()
  70 function
  71 is like
  72 .BR opendir (),
  73 but returns a directory stream for the directory referred
  74 to by the open file descriptor
  75 .IR fd .
  76 After a successful call to
  77 .BR fdopendir (),
  78 .I fd
  79 is used internally by the implementation,
  80 and should not otherwise be used by the application.
  81 .SH RETURN VALUE
  82 The
  83 .BR opendir ()
  84 and
  85 .BR fdopendir ()
  86 functions return a pointer to the directory stream.
  87 On error, NULL is returned, and
  88 .I errno
  89 is set appropriately.
  90 .SH ERRORS
  91 .TP
  92 .B EACCES
  93 Permission denied.
  94 .TP
  95 .B EBADF
  96 .I fd
  97 is not a valid file descriptor opened for reading.
  98 .TP
  99 .B EMFILE
 100 Too many file descriptors in use by process.
 101 .TP
 102 .B ENFILE
 103 Too many files are currently open in the system.
 104 .TP
 105 .B ENOENT
 106 Directory does not exist, or \fIname\fP is an empty string.
 107 .TP
 108 .B ENOMEM
 109 Insufficient memory to complete the operation.
 110 .TP
 111 .B ENOTDIR
 112 \fIname\fP is not a directory.
 113 .SH VERSIONS
 114 .BR fdopendir ()
 115 is available in glibc since version 2.4.
 116 .SH CONFORMING TO
 117 .BR opendir ()
 118 is present on SVr4, 4.3BSD, and specified in POSIX.1-2001.
 119 .BR fdopendir ()
 120 is specified in POSIX.1-2008.
 121 .SH NOTES
 122 The underlying file descriptor of the directory stream can be obtained using
 123 .BR dirfd (3).
 124
 125 The
 126 .BR opendir ()
 127 function sets the close-on-exec flag for the file descriptor underlying the
 128 .IR "DIR *" .
 129 The
 130 .BR fdopendir ()
 131 function leaves the setting of the close-on-exec
 132 flag unchanged for the file descriptor,
 133 .IR fd .
 134 POSIX.1-200x leaves it unspecified whether a successful call to
 135 .BR fdopendir ()
 136 will set the close-on-exec flag for the file descriptor,
 137 .IR fd .
 138 .SH SEE ALSO
 139 .BR open (2),
 140 .BR closedir (3),
 141 .BR dirfd (3),
 142 .BR readdir (3),
 143 .BR rewinddir (3),
 144 .BR scandir (3),
 145 .BR seekdir (3),
 146 .BR telldir (3)