LINK(2) 						     Linux Programmer's Manual							   LINK(2)

NAME

       link - make a new name for a file

SYNOPSIS

       #include <unistd.h>

       int link(const char *oldpath, const char *newpath);

DESCRIPTION

       link() creates a new link (also known as a hard link) to an existing file.

       If newpath exists it will not be overwritten.

       This new name may be used exactly as the old one for any operation; both names refer to the same file (and so have the same permissions and
       ownership) and it is impossible to tell which name was the "original".

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EACCES Write access to the directory containing newpath is denied, or search permission is denied for one of the directories  in  the  path
	      prefix of oldpath or newpath.  (See also path_resolution(7).)

       EEXIST newpath already exists.

       EFAULT oldpath or newpath points outside your accessible address space.

       EIO    An I/O error occurred.

       ELOOP  Too many symbolic links were encountered in resolving oldpath or newpath.

       EMLINK The file referred to by oldpath already has the maximum number of links to it.

       ENAMETOOLONG
	      oldpath or newpath was too long.

       ENOENT A directory component in oldpath or newpath does not exist or is a dangling symbolic link.

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing the file has no room for the new directory entry.

       ENOTDIR
	      A component used as a directory in oldpath or newpath is not, in fact, a directory.

       EPERM  oldpath is a directory.

       EPERM  The file system containing oldpath and newpath does not support the creation of hard links.

       EROFS  The file is on a read-only file system.

       EXDEV  oldpath  and  newpath  are  not on the same mounted file system.	(Linux permits a file system to be mounted at multiple points, but
	      link() does not work across different mount points, even if the same file system is mounted on both.)

CONFORMING TO

       SVr4, 4.3BSD, POSIX.1-2001 (but see NOTES).

NOTES

       Hard links, as created by link(), cannot span file systems.  Use symlink(2) if this is required.

       POSIX.1-2001 says that link() should dereference oldpath if it is a symbolic link.  However, since kernel 2.0, Linux does  not  do  so:	if
       oldpath	is a symbolic link, then newpath is created as a (hard) link to the same symbolic link file (i.e., newpath becomes a symbolic link
       to the same file that oldpath refers to).  Some other implementations behave in the same manner as Linux.  POSIX.1-2008 changes the  speci-
       fication  of  link(), making it implementation-dependent whether or not oldpath is dereferenced if it is a symbolic link.  For precise con-
       trol over the treatment of symbolic links when creating a link, see linkat(2).

BUGS

       On NFS file systems, the return code may be wrong in case the NFS server performs the link creation and dies before it  can  say  so.   Use
       stat(2) to find out if the link got created.

SEE ALSO

       ln(1), linkat(2), open(2), rename(2), stat(2), symlink(2), unlink(2), path_resolution(7), symlink(7)

COLOPHON

       This  page is part of release 3.25 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/.

Linux								    2008-08-21								   LINK(2)