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).)

       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 fact, a directory.

       EPERM  oldpath is a directory.

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

       EPERM (since Linux 3.6)
              The caller does not have permission to create a hard link to this file  (see  the  description  of
              /proc/sys/fs/protected_hardlink in proc(5)).

       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 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 specification 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/.