LINK(2) BSD Programmer's Manual LINK(2)
link - make a hard file link
link(const char *name1, const char *name2);
The 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 ob-
ject is incremented; name1 and name2 share equal access and rights to the
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. Unless the caller is the super-user,
name1 may not be a directory.
Upon successful completion, a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
Link() will fail and no link will be created if:
[ENOTDIR] A component of either path prefix is not a directory.
[EINVAL] Either pathname contains a character with the high-order
A component of either pathname exceeded 255 characters, or
entire length of either path name exceeded 1023 characters.
[ENOENT] A component of either path prefix does not exist.
[EACCES] A component of either path prefix denies search permission.
[EACCES] The requested link requires writing in a directory with a
mode that denies write permission.
[ELOOP] Too many symbolic links were encountered in translating one
of the pathnames.
[ENOENT] The file named by name1 does not exist.
[EEXIST] The link named by name2 does exist.
[EPERM] The file named by name1 is a directory and the effective
user ID is not super-user.
[EXDEV] The link named by name2 and the file named by name1 are on
different file systems.
[ENOSPC] 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.
[EDQUOT] 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
[EIO] An I/O error occurred while reading from or writing to the
file system to make the directory entry.
[EROFS] The requested link requires writing in a directory on a
read-only file system.
[EFAULT] One of the pathnames specified is outside the process's al-
located address space.
Link() is expected to conform to IEEE Std 1003.1-1988 (``POSIX'').
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