LINK(2)



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_resolu-
              tion(2).)

       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  filesystem  containing oldpath and newpath does not support
              the creation of hard links.

       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(2) does not work across different mount points, even if
              the same filesystem is mounted on both.)

NOTES
       Hard  links,  as  created  by link(), cannot span filesystems. Use sym-
       link() if this is required.

       POSIX.1-2001 says that link() should dereference oldpath  if  it  is  a
       symbolic link.  However, 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 man-
       ner as Linux.

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001 (except as noted above).

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), path_resolution(2), rename(2), stat(2), sym-
       link(2), unlink(2)

Linux 2.6.7                       2004-06-23                           LINK(2)

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