FHLINK(2)                 FreeBSD System Calls Manual                FHLINK(2)

NAME
     fhlink, fhlinkat - make a hard file link

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     fhlink(fhandle_t *fhp, const char *to);

     int
     fhlinkat(fhandle_t *fhp, int tofd, const char *to);

DESCRIPTION
     The fhlink() system call atomically creates the specified directory entry
     (hard link) to with the attributes of the underlying object pointed at by
     fhp.  If the link is successful: the link count of the underlying object
     is incremented; fhp and to share equal access and rights to the
     underlying object.

     If fhp is removed, the file to is not deleted and the link count of the
     underlying object is decremented.

     The object pointed at by the fhp argument must exist for the hard link to
     succeed and both fhp and to must be in the same file system.  The fhp
     argument may not be a directory.

     The fhlinkat() system call is equivalent to fhlink except in the case
     where to is a relative paths.  In this case a relative path to is
     interpreted relative to the directory associated with the file descriptor
     tofd instead of the current working directory.

     If fhlinkat() is passed the special value AT_FDCWD in the tofd parameter,
     the current working directory is used for the to argument.  If tofd has
     value AT_FDCWD, the behavior is identical to a call to link().  Unless
     flag contains the AT_SYMLINK_FOLLOW flag, if fhp names a symbolic link, a
     new link is created for the symbolic link fhp and not its target.

RETURN VALUES
     The link() function returns the value 0 if successful; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     The fhlink() system call will fail and no link will be created if:

     [ENOTDIR]          A component of to prefix is not a directory.

     [ENAMETOOLONG]     A component of to exceeded 255 characters, or entire
                        length of to name exceeded 1023 characters.

     [ENOENT]           A component of to prefix does not exist.

     [EOPNOTSUPP]       The file system containing the file pointed at by fhp
                        does not support links.

     [EMLINK]           The link count of the file pointed at by fhp would
                        exceed 32767.

     [EACCES]           A component of to 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 pointed at by fhp does not exist.

     [EEXIST]           The link named by to does exist.

     [EPERM]            The file pointed at by fhp is a directory.

     [EPERM]            The file pointed at by fhp has its immutable or
                        append-only flag set, see the chflags(2) manual page
                        for more information.

     [EPERM]            The parent directory of the file named by to has its
                        immutable flag set.

     [EXDEV]            The link named by to and the file pointed at by fhp
                        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 exhausted.

     [EIO]              An I/O error occurred while reading from or writing to
                        the file system to make the directory entry.

     [EINTEGRITY]       Corrupted data was detected while reading from the
                        file system.

     [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 allocated address space.

     [ESTALE]           The file handle fhp is no longer valid

     In addition to the errors returned by the fhlink(), the fhlinkat() system
     call may fail if:

     [EBADF]            The fhp or to argument does not specify an absolute
                        path and the tofd argument, is not AT_FDCWD nor a
                        valid file descriptor open for searching.

     [EINVAL]           The value of the flag argument is not valid.

     [ENOTDIR]          The fhp or to argument is not an absolute path and
                        tofd is not AT_FDCWD nor a file descriptor associated
                        with a directory.

SEE ALSO
     fhopen(2), fhreadlink(2), fhstat(2)

FreeBSD 13.1-RELEASE-p6        February 23, 2021       FreeBSD 13.1-RELEASE-p6