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LINK(2)			  FreeBSD System Calls Manual		       LINK(2)

NAME
     link, linkat -- make hard link to a file

SYNOPSIS
     #include <unistd.h>

     int
     link(const	char *name1, const char	*name2);

     #include <fcntl.h>
     #include <unistd.h>

     int
     linkat(int	fd1, const char	*name1,	int fd2, const char *name2, int	flag);

DESCRIPTION
     The link()	function atomically creates the	specified directory entry
     (hard link) name2 with the	attributes of the underlying object pointed at
     by	name1.	If the link is successful: the link count of the underlying
     object is incremented; name1 and name2 share equal	access and rights to
     the underlying object.

     If	name1 is removed, the file name2 is not	deleted	and the	link count of
     the underlying object is decremented.

     name1 must	exist for the hard link	to succeed and both name1 and name2
     must be in	the same file system.  As mandated by POSIX.1 name1 may	not be
     a directory.

     The linkat() function is equivalent to link() except that where name1 or
     name2 specifies a relative	path, the directory entries linked are re-
     solved relative to	the directories	associated with	file descriptors fd1
     or	fd2 (respectively) instead of the current working directory.

     If	linkat() is passed the special value AT_FDCWD (defined in <fcntl.h>)
     in	the fd1	or fd2 parameter, the current working directory	is used	for
     resolving the respective name1 or name2 argument.

     The flag argument is the bitwise OR of zero or more of the	following val-
     ues:

	   AT_SYMLINK_FOLLOW  If name1 names a symbolic	link, a	new link for
			      the target of the	symbolic link is created.

     If	the AT_SYMLINK_FOLLOW flag is clear and	name1 names a symbolic link, a
     new link is created for the symbolic link name1 and not its target.

RETURN VALUES
     Upon successful completion, the value 0 is	returned; otherwise the
     value -1 is returned and the global variable errno	is set to indicate the
     error.

ERRORS
     link() and	linkat() will fail and no link will be created if:

     [ENOTDIR]		A component of either path prefix is not a directory.

     [ENAMETOOLONG]	A component of a pathname exceeded NAME_MAX charac-
			ters, or an entire pathname (including the terminating
			NUL) exceeded PATH_MAX bytes.

     [ENOENT]		A component of either path prefix does not exist.

     [EOPNOTSUPP]	The file system	containing the file named by name1
			does not support links.

     [EMLINK]		The link count of the file named by name1 would	exceed
			LINK_MAX.

     [EACCES]		A component of either path prefix denies search	per-
			mission.

     [EACCES]		The requested link requires writing in a directory
			with a mode that denies	write permission.

     [ELOOP]		Too many symbolic links	were encountered in translat-
			ing one	of the pathnames.

     [ENOENT]		The file named by name1	does not exist.

     [EEXIST]		The link named by name2	does exist.

     [EPERM]		The file named by name1	is a directory and the effec-
			tive user ID is	not superuser, or the file system con-
			taining	the file does not permit the use of link() on
			a directory.

     [EPERM]		The file named by name1	is flagged immutable or	ap-
			pend-only.

     [EXDEV]		The link named by name2	and the	file named by name1
			are on different file systems.

     [ENOSPC]		The directory in which the entry for the new link is
			being placed cannot be extended	because	there is no
			space left on the file system containing the direc-
			tory.

     [EDQUOT]		The directory in which the entry for the new link is
			being placed cannot be extended	because	the user's
			quota of disk blocks on	the file system	containing the
			directory has been exhausted.

     [EIO]		An I/O error occurred while reading from or writing to
			the file system	to make	the directory entry.

     [EROFS]		The requested link requires writing in a directory on
			a read-only file system.

     [EFAULT]		One of the pathnames specified is outside the
			process's allocated address space.

     Additionally, linkat() will fail if:

     [EINVAL]		The value of the flag argument was neither zero	nor
			AT_SYMLINK_FOLLOW.

     [EBADF]		The name1 or name2 argument specifies a	relative path
			and the	fd1 or fd2 argument, respectively, is neither
			AT_FDCWD nor a valid file descriptor.

     [ENOTDIR]		The name1 or name2 argument specifies a	relative path
			and the	fd1 or fd2 argument, respectively, is a	valid
			file descriptor	but it does not	reference a directory.

     [EACCES]		The name1 or name2 argument specifies a	relative path
			but search permission is denied	for the	directory
			which the fd1 or fd2 file descriptor, respectively,
			references.

SEE ALSO
     ln(1), readlink(2), symlink(2), unlink(2)

STANDARDS
     The link()	and linkat() functions are expected to conform to IEEE Std
     1003.1-2008 ("POSIX.1").

HISTORY
     The link()	system call first appeared in Version 1	AT&T UNIX.  The
     linkat() function appeared	in OpenBSD 5.0.

FreeBSD	13.0		      September	10, 2015		  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY

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