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symlink(2)
NAME
symlink - Make a symbolic link to a file
SYNOPSIS
#include <unistd.h>
int symlink(
const char *path1,
const char *path2 );
STANDARDS
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.
PARAMETERS
path1
Specifies the contents of the symbolic link to create.
path2
Names the symbolic link to be created.
DESCRIPTION
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:
link()
An error is returned if a symbolic link is named by the path2
parameter.
lstat()
If the file specified is a symbolic link, the status of the link itself
is returned.
mknod()
An error is returned if a symbolic link is named as the path parameter.
readlink()
This call applies only to symbolic links.
remove()
A symbolic link can be removed by invoking the remove() function.
rename()
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.
rmdir()
An error is returned if a symbolic link is named as the path parameter.
symlink()
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.
unlink()
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.
RETURN VALUES
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.
ERRORS
If the symlink() function fails, errno may be set to one of the following
values:
[EACCES]
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.
[EDQUOT]
[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.
[EEXIST]
The path specified by the path2 parameter already exists.
[ELOOP]
Too many symbolic links are found in translating path2.
[ENAMETOOLONG]
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.
[ENOENT]
The path2 parameter points to a null pathname, or a component of path2
does not exist.
[ENOSPC]
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.
[ENOSYS]
[Tru64 UNIX] The operation is not applicable for this file system
type.
[ENOTDIR]
A component of path2 is not a directory.
[EROFS]
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:
[ENFILE]
Indicates either that the system file table is full, or that there are
too many files currently open in the system.
[ESTALE]
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.
SEE ALSO
Commands: ln(1), cdslinvchk(8)
Functions: link(2), readlink(2), unlink(2)
Others: hier(5), standards(5)
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