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linkat - create a file link relative to directory file descriptors
#include <fcntl.h> /* Definition of AT_* constants */
int linkat(int olddirfd, const char *oldpath,
int newdirfd, const char *newpath, int flags);
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.
On success, linkat() returns 0. On error, -1 is returned and errno is
set to indicate the error.
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.
oldpath is relative and olddirfd is a file descriptor referring
to a file other than a directory; or similar for newpath and
linkat() was added to Linux in kernel 2.6.16.
This system call is non-standard but is proposed for inclusion in a
future revision of POSIX.1.
See openat(2) for an explanation of the need for linkat().
link(2), openat(2), path_resolution(7)
This page is part of release 2.77 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/.