NAME


linkat - create a file link relative to directory file descriptors

SYNOPSIS


#define _ATFILE_SOURCE #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h>

int linkat(int olddirfd, const char *oldpath, int newdirfd, const char *newpath, int flags);

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 3.23 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/.

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