link


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_resolu-
              tion(7).)

       EDQUOT The user's quota of disk  blocks  on  the  filesystem  has  been
              exhausted.

       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

       EROFS  The file is on a read-only filesystem.

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

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

NOTES
       Hard links, as created by link(), cannot span  filesystems.   Use  sym-
       link(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  specifi-
       cation  of  link(),  making  it implementation-dependent whether or not
       oldpath is dereferenced if it is a symbolic link.  For precise  control
       over  the  treatment  of  symbolic  links  when  creating  a  link, see
       linkat(2).

BUGS
       On NFS filesystems, 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 3.54 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                             2013-01-27                           LINK(2)
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