symlink - Make a symbolic link to a file
#include <unistd.h>
int symlink(
const char *path1,
const char *path2 );
Interfaces documented on this reference page conform to
industry standards as follows:
symlink(): XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies the contents of the symbolic link to create.
Names the symbolic link to be created.
The symlink() function creates a symbolic link with the
name specified by the path2 parameter which refers to the
file named by the path1 parameter.
Like a hard link, which is described in link(2), a symbolic
link allows a file to have multiple names. The presence
of a hard link guarantees the existence of a file,
even after the original name has been removed. A symbolic
link provides no such assurance; in fact, the file named
by the path1 parameter need not exist when the link is
created. Unlike hard links, a symbolic link can cross file
system boundaries.
When a component of a pathname refers to a symbolic link
rather than a directory, the pathname contained in the
symbolic link is resolved. If the pathname in the symbolic
link starts with a / (slash), the symbolic link pathname
is resolved relative to the process root directory. If the
pathname in the symbolic link does not start with a /
(slash), the symbolic link pathname is resolved relative
to the directory that contains the symbolic link.
If the symbolic link is the last component of the original
pathname, remaining components of the original pathname
are appended to the contents of the link and pathname resolution
continues.
The symbolic link pathname may or may not be traversed,
depending on which function is being performed. Most functions
traverse the link.
The functions which refer only to the symbolic link
itself, rather than to the object to which the link
refers, are: An error is returned if a symbolic link is
named by the path2 parameter. If the file specified is a
symbolic link, the status of the link itself is returned.
An error is returned if a symbolic link is named as the
path parameter. This call applies only to symbolic links.
A symbolic link can be removed by invoking the remove()
function. If the file to be renamed is a symbolic link,
the symbolic link is renamed. If the new name refers to an
existing symbolic link, the symbolic link is destroyed.
An error is returned if a symbolic link is named as the
path parameter. An error is returned if the symbolic link
named by the path2 parameter already exists. A symbolic
link can be created that refers to another symbolic link;
that is, the path1 parameter can refer to a symbolic link.
A symbolic link can be removed by invoking unlink().
Search access to the symbolic link is required to traverse
the pathname contained therein. Normal permission checks
are made on each component of the symbolic link pathname
during its resolution.
[Tru64 UNIX] A Context Dependent Symbolic Link (CDSL) is
a symbolic link that has a variable in the pathname. The
variable is resolved differently for each member system in
a cluster. If the system is not a member of a cluster, the
variable is resolved as if it were member0 of a cluster.
See hier(5) for more information about CDSLs and the
cdslinvchk(8) reference page for information about checking
the CDSL file inventory.
Upon successful completion, the symlink() function returns
a value of 0 (zero). If the symlink() function fails, a
value of -1 is returned and errno is set to indicate the
error.
If the symlink() function fails, errno may be set to one
of the following values: The requested operation requires
writing in a directory with a mode that denies write permission,
or search permission is denied on a component of
path2. [Tru64 UNIX] The directory in which the entry for
the symbolic 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 path
specified by the path2 parameter already exists. Too many
symbolic links are found in translating path2. The length
of the path1 parameter or path2 parameter exceeds
PATH_MAX, or a pathname component of path2 is longer than
NAME_MAX while _POSIX_NO_TRUNC is in effect.
Pathname resolution of a symbolic link produced an
intermediate result whose length exceeds PATH_MAX.
The path2 parameter points to a null pathname, or a
component of path2 does not exist. The directory
in which the entry for the symbolic link is being
placed cannot be extended because there is no space
left on the file system containing the directory.
The new symbolic link cannot be created because
there is no space left on the file system which
would contain the link.
There are no free inodes on the file system on
which the file is being created. [Tru64 UNIX] The
operation is not applicable for this file system
type. A component of path2 is not a directory.
The requested operation requires writing in a
directory on a read-only file system.
[Tru64 UNIX] For NFS file access, if the symlink()
function fails, errno may also be set to one of the following
values: Indicates either that the system file table
is full, or that 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 either unmounted or unexported
by the server.
Commands: ln(1), cdslinvchk(8)
Functions: link(2), readlink(2), unlink(2)
Others: hier(5), standards(5)
symlink(2)
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