man2/fstatat.2

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  25 .TH FSTATAT 2 2012-05-04 "Linux" "Linux Programmer's Manual"
  26 .SH NAME
  27 fstatat \- get file status relative to a directory file descriptor
  28 .SH SYNOPSIS
  29 .nf
  30 .B #include <fcntl.h>           /* Definition of AT_* constants */
  31 .B #include <sys/stat.h>
  32 .sp
  33 .BI "int fstatat(int " dirfd ", const char *" pathname ", struct stat *" \
  34 buf ,
  35 .BI "            int " flags );
  36 .fi
  37 .sp
  38 .in -4n
  39 Feature Test Macro Requirements for glibc (see
  40 .BR feature_test_macros (7)):
  41 .in
  42 .sp
  43 .BR fstatat ():
  44 .PD 0
  45 .ad l
  46 .RS 4
  47 .TP 4
  48 Since glibc 2.10:
  49 _XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
  50 .TP
  51 Before glibc 2.10:
  52 _ATFILE_SOURCE
  53 .RE
  54 .ad
  55 .PD
  56 .SH DESCRIPTION
  57 The
  58 .BR fstatat ()
  59 system call operates in exactly the same way as
  60 .BR stat (2),
  61 except for the differences described in this manual page.
  62
  63 If the pathname given in
  64 .I pathname
  65 is relative, then it is interpreted relative to the directory
  66 referred to by the file descriptor
  67 .I dirfd
  68 (rather than relative to the current working directory of
  69 the calling process, as is done by
  70 .BR stat (2)
  71 for a relative pathname).
  72
  73 If
  74 .I pathname
  75 is relative and
  76 .I dirfd
  77 is the special value
  78 .BR AT_FDCWD ,
  79 then
  80 .I pathname
  81 is interpreted relative to the current working
  82 directory of the calling process (like
  83 .BR stat (2)).
  84
  85 If
  86 .I pathname
  87 is absolute, then
  88 .I dirfd
  89 is ignored.
  90
  91 .I flags
  92 can either be 0, or include one or more of the following flags ORed:
  93 .TP
  94 .BR AT_NO_AUTOMOUNT " (since Linux 2.6.38)"
  95 Don't automount the terminal ("basename") component of
  96 .I pathname
  97 if it is a directory that is an automount point.
  98 This allows the caller to gather attributes of an automount point
  99 (rather than the location it would mount).
 100 This flag can be used in tools that scan directories
 101 to prevent mass-automounting of a directory of automount points.
 102 The
 103 .B AT_NO_AUTOMOUNT
 104 flag has no effect if the mount point has already been mounted over.
 105 .TP
 106 .B AT_SYMLINK_NOFOLLOW
 107 If
 108 .I pathname
 109 is a symbolic link, do not dereference it:
 110 instead return information about the link itself, like
 111 .BR lstat (2).
 112 (By default,
 113 .BR fstatat ()
 114 dereferences symbolic links, like
 115 .BR stat (2).)
 116 .SH RETURN VALUE
 117 On success,
 118 .BR fstatat ()
 119 returns 0.
 120 On error, \-1 is returned and
 121 .I errno
 122 is set to indicate the error.
 123 .SH ERRORS
 124 The same errors that occur for
 125 .BR stat (2)
 126 can also occur for
 127 .BR fstatat ().
 128 The following additional errors can occur for
 129 .BR fstatat ():
 130 .TP
 131 .B EBADF
 132 .I dirfd
 133 is not a valid file descriptor.
 134 .TP
 135 .B EINVAL
 136 Invalid flag specified in
 137 .IR flags .
 138 .TP
 139 .B ENOTDIR
 140 .I pathname
 141 is relative and
 142 .I dirfd
 143 is a file descriptor referring to a file other than a directory.
 144 .SH VERSIONS
 145 .BR fstatat ()
 146 was added to Linux in kernel 2.6.16;
 147 library support was added to glibc in version 2.4.
 148 .SH CONFORMING TO
 149 POSIX.1-2008.
 150 A similar system call exists on Solaris.
 151 .SH NOTES
 152 See
 153 .BR openat (2)
 154 for an explanation of the need for
 155 .BR fstatat ().
 156
 157 The underlying system call employed by the glibc
 158 .BR fstatat ()
 159 wrapper function is actually called
 160 .BR fstatat64 ().
 161 .SH SEE ALSO
 162 .BR openat (2),
 163 .BR stat (2),
 164 .BR path_resolution (7),
 165 .BR symlink (7)