LINK(2) | System Calls Manual | LINK(2) |
link
—
#include <unistd.h>
int
link
(const
char *name1, const char
*name2);
#include
<fcntl.h>
int
linkat
(int
fd1, const char
*name1, int fd2,
const char *name2,
int flags);
link
() function call atomically creates the
specified directory entry (hard link) name2 with the
attributes of the underlying object pointed at by name1.
If the link is successful: the link count of the underlying object is
incremented; name1 and name2 share
equal access and rights to the underlying object.
If name1 is removed, the file name2 is not deleted and the link count of the underlying object is decremented.
name1 must exist for the hard link to succeed and both name1 and name2 must be in the same file system. name1 may not be a directory unless the caller is the super-user and the file system containing it supports linking to directories.
linkat
() works the same way as
link
() except if name1 (resp.
name2) is relative. In that case, it is looked up from
a directory whose file descriptor was passed as fd1
(resp. fd2). Search permission is required on the
directories named by fd1 and
fd2. fd1 or
fd2 can be set to AT_FDCWD
in
order to specify the current directory.
When operating on a symlink, link
()
resolves the symlink and creates a hard link on the target.
linkat
() will do the same if
AT_SYMLINK_FOLLOW
is set in
flags, but it will link on the symlink itself if the
flag is clear.
link
() and linkat
()
functions return the value 0 if successful; otherwise the
value -1 is returned and the global variable
errno is set to indicate the error.
link
() and linkat
() will fail
and no link will be created if:
EACCES
]EDQUOT
]EEXIST
]EFAULT
]EIO
]ELOOP
]EMLINK
]LINK_MAX
}.ENAMETOOLONG
]NAME_MAX
}
characters, or an entire path name exceeded
{PATH_MAX
} characters.ENOENT
]ENOSPC
]ENOTDIR
]EOPNOTSUPP
]EPERM
]link
() on a
directory.EROFS
]EXDEV
]In addition, linkat
() will fail if:
EBADF
]AT_FDCWD
nor a valid file descriptor open for
reading or searching.ENOTDIR
]link
() function conforms to IEEE
Std 1003.1-1990 (“POSIX.1”).
linkat
() conforms to IEEE Std
1003.1-2008 (“POSIX.1”).
link
() function appeared in
Version 1 AT&T UNIX.
September 1, 2019 | NetBSD 9.0 |