symlink
, symlinkat
—
make symbolic link to a file
Standard C Library (libc, -lc)
#include <unistd.h>
int
symlink
(const
char *name1, const char
*name2);
int
symlinkat
(const
char *name1, int
fd, const char
*name2);
A symbolic link name2 is created to
name1 (name2 is the name of the
file created, name1 is the string used in creating the
symbolic link). Either name may be an arbitrary path name; the files need
neither to be on the same file system nor to exist.
symlinkat
() works the same way as
symlink
() except if path2 is
relative. In that case, it is looked up from a directory whose file
descriptor was passed as fd. Search permission is
required on this directory. fd can be set to
AT_FDCWD
in order to specify the current
directory.
The symlink
() and symlinkat
()
functions return the value 0 if successful; otherwise the
value -1 is returned and the global variable
errno is set to indicate the error.
symlink
() and symlinkat
() will
fail and no link will be created if:
- [
EACCES
]
- A component of the name2 path prefix denies search
permission.
- [
EDQUOT
]
- The directory in which the entry for the new 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. Or, the new symbolic
link cannot be created because the user's quota of disk blocks on the file
system that will contain the symbolic link has been exhausted. Or, the
user's quota of inodes on the file system on which the symbolic link is
being created has been exhausted.
- [
EEXIST
]
- name2 already exists.
- [
EFAULT
]
- name1 or name2 points outside
the process's allocated address space.
- [
EIO
]
- An I/O error occurred while making the directory entry for
name2, or allocating the inode for
name2, or writing out the link contents of
name2. Or, an I/O error occurred while making the
directory entry or allocating the inode.
- [
ELOOP
]
- Too many symbolic links were encountered in translating the pathname.
- [
ENAMETOOLONG
]
- A component of a pathname exceeded {
NAME_MAX
}
characters, or an entire path name exceeded
{PATH_MAX
} characters.
- [
ENOENT
]
- A component of the name2 path does not exist.
- [
ENOSPC
]
- The directory in which the entry for the new symbolic link is being placed
cannot be extended because there is no space left on the file system
containing the directory. Or, the new symbolic link cannot be created
because there there is no space left on the file system that will contain
the symbolic link. Or, there are no free inodes on the file system on
which the symbolic link is being created.
- [
ENOTDIR
]
- A component of the name2 prefix is not a
directory.
- [
EROFS
]
- The file name2 would reside on a read-only file
system.
In addition, symlinkat
() will fail if:
- [
EBADF
]
- name2 does not specify an absolute path and
fd is neither
AT_FDCWD
nor a
valid file descriptor open for reading or searching.
- [
ENOTDIR
]
- name2 is not an absolute path and
fd is a file descriptor associated with a
non-directory file.
The symlink
() function conforms to IEEE
Std 1003.1-1990 (“POSIX.1”).
symlinkat
() conforms to IEEE Std
1003.1-2008 (“POSIX.1”).
The symlink
() function call appeared in
4.2BSD.