LINKAT
Section: Linux Programmer's Manual (2)
Updated: 2009-12-13
NAME
linkat - create a file link relative to directory file descriptors
SYNOPSIS
#include <fcntl.h> /* Definition of AT_* constants */
#include <unistd.h>
int linkat(int olddirfd, const char *oldpath,
int newdirfd, const char *newpath, int flags);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
linkat():
-
- Since glibc 2.10:
-
_XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
- Before glibc 2.10:
-
_ATFILE_SOURCE
DESCRIPTION
The
linkat()
system call operates in exactly the same way as
link(2),
except for the differences described in this manual page.
If the pathname given in
oldpath
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
olddirfd
(rather than relative to the current working directory of
the calling process, as is done by
link(2)
for a relative pathname).
If
oldpath
is relative and
olddirfd
is the special value
AT_FDCWD,
then
oldpath
is interpreted relative to the current working
directory of the calling process (like
link(2)).
If
oldpath
is absolute, then
olddirfd
is ignored.
The interpretation of
newpath
is as for
oldpath,
except that a relative pathname is interpreted relative
to the directory referred to by the file descriptor
newdirfd.
By default,
linkat(),
does not dereference
oldpath
if it is a symbolic link (like
link(2)).
Since Linux 2.6.18, the flag
AT_SYMLINK_FOLLOW
can be specified in
flags
to cause
oldpath
to be dereferenced if it is a symbolic link.
Before kernel 2.6.18, the
flags
argument was unused, and had to be specified as 0.
RETURN VALUE
On success,
linkat()
returns 0.
On error, -1 is returned and
errno
is set to indicate the error.
ERRORS
The same errors that occur for
link(2)
can also occur for
linkat().
The following additional errors can occur for
linkat():
- EBADF
-
olddirfd
or
newdirfd
is not a valid file descriptor.
- ENOTDIR
-
oldpath
is relative and
olddirfd
is a file descriptor referring to a file other than a directory;
or similar for
newpath
and
newdirfd
VERSIONS
linkat()
was added to Linux in kernel 2.6.16.
CONFORMING TO
POSIX.1-2008.
NOTES
See
openat(2)
for an explanation of the need for
linkat().
SEE ALSO
link(2),
openat(2),
path_resolution(7),
symlink(7)
COLOPHON
This page is part of release 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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Time: 07:34:53 GMT, March 26, 2013