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).)

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

NOTES
       Hard  links,  as created by link(), cannot span file systems.  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  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 3.35 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://man7.org/linux/man-pages/.



Linux                             2008-08-21                           LINK(2)
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