link - Create a hard link to an existing file on the local
file system
#include <unistd.h>
int link(
const char *path1,
const char *path2 );
Interfaces documented on this reference page conform to
industry standards as follows:
link(): XSH4.0, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to the pathname of an existing file. Points to the
pathname for the directory entry to be created. If the
path2 parameter names a symbolic link, an error is
returned.
The link() function creates an additional hard link
(directory entry) for an existing file. The old and the
new link share equal access rights to the underlying
object. The link() function atomically creates a new link
for the existing file and increments the link count of the
file by one.
Both the path1 and path2 parameters must reside on the
same file system. A hard link to a directory cannot be
created.
Upon successful completion, the link() function marks the
st_ctime field of the file for update, and marks the
st_ctime and st_mtime fields of the directory containing
the new entry for update.
A process must have write permission in the target directory
with respect to all access control policies configured
on the system.
See symlink(2) for information about making symbolic
links, including Context Dependent Symbolic Links (CDSLs).
Upon successful completion, the link() function returns a
value of 0 (zero). If the link() function fails, a value
of -1 is returned, no link is created, and errno is set to
indicate the error.
If the link() function fails, errno may be set to one of
the following values: The requested link requires writing
in a directory with a mode that denies write permission,
or a component of either the path1 or path2 parameter
denies search permission.
The requested link requires writing in a directory
to which the process does not have write access
with respect to one or more of the system's configured
access policies. [Tru64 UNIX] The directory
in which the entry for the new link is being placed
cannot be extended because the user's quota of disk
blocks on the file system containing the directory
has been exhausted. The link named by the path2
parameter already exists. [Tru64 UNIX] The path1
or path2 parameter is an invalid address. [Tru64
UNIX] An I/O error occurred when updating the
directory. Too many links were encountered in
translating path1 or path2. The number of links to
the file named by path1 would exceed LINK_MAX. The
length of the path1 or path2 string exceeds
PATH_MAX or a pathname component is longer than
NAME_MAX. The file named by the path1 parameter
does not exist or the path1 or path2 parameter is
an empty string. The directory in which the entry
for the new link is being placed cannot be extended
because there is no space left on the file system
containing the directory. A component of either
path prefix is not a directory. The file named by
the path1 parameter is a directory. The requested
link requires writing in a directory on a read-only
file system. The link named by the path2 parameter
and the file named by the path1 parameter are on
different file systems, or path1 refers to a
STREAM.
[Tru64 UNIX] For NFS file access, if the link() function
fails, errno may also be set to one of the following values:
Indicates that the system file table is full or there
are too many files currently open in the system. Indicates
a stale NFS file handle. An opened file was deleted
by the server or another client; a client cannot open a
file because the server has unmounted or unexported the
remote directory; or the directory that contains an opened
file was unmounted or unexported by the server.
Commands: link(1), unlink(1)
Functions: symlink(2), unlink(2)
Others: standards(5)
link(2)
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