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@(#)link.2 8.3 (Berkeley) 1/12/94
$Id: link.2,v 1.5 1996/12/02 20:03:37 wosch Exp $
.Dd January 12, 1994 .Dt LINK 2 .Os BSD 4 .Sh NAME .Nm link .Nd make a hard file link .Sh SYNOPSIS .Fd #include <unistd.h> .Ft int .Fn link "const char *name1" "const char *name2" .Sh DESCRIPTION The .Fn link function call atomically creates the specified directory entry (hard link) .Fa name2 with the attributes of the underlying object pointed at by .Fa name1 If the link is successful: the link count of the underlying object is incremented; .Fa name1 and .Fa name2 share equal access and rights to the underlying object.
p If .Fa name1 is removed, the file .Fa name2 is not deleted and the link count of the underlying object is decremented.
p .Fa Name1 must exist for the hard link to succeed and both .Fa name1 and .Fa name2 must be in the same file system. .Fa name1 may not be a directory. .Sh RETURN VALUES Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and .Va errno is set to indicate the error. .Sh ERRORS .Fn Link will fail and no link will be created if: l -tag -width Ar t Bq Er ENOTDIR A component of either path prefix is not a directory. t Bq Er ENAMETOOLONG A component of either pathname exceeded 255 characters, or entire length of either path name exceeded 1023 characters. t Bq Er ENOENT A component of either path prefix does not exist. t Bq Er EACCES A component of either path prefix denies search permission. t Bq Er EACCES The requested link requires writing in a directory with a mode that denies write permission. t Bq Er ELOOP Too many symbolic links were encountered in translating one of the pathnames. t Bq Er ENOENT The file named by .Fa name1 does not exist. t Bq Er EEXIST The link named by .Fa name2 does exist. t Bq Er EPERM The file named by .Fa name1 is a directory. t Bq Er EXDEV The link named by .Fa name2 and the file named by .Fa name1 are on different file systems. t Bq Er 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. t Bq Er 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. t Bq Er EIO An I/O error occurred while reading from or writing to the file system to make the directory entry. t Bq Er EROFS The requested link requires writing in a directory on a read-only file system. t Bq Er EFAULT One of the pathnames specified is outside the process's allocated address space. .El .Sh SEE ALSO .Xr symlink 2 , .Xr unlink 2 .Sh STANDARDS The .Fn link function call is expected to conform to .St -p1003.1-90 . .Sh HISTORY A .Fn link function call appeared in .At v7 .
p The .Fn link system call traditionally allows the super-user to link directories which corrupts the filesystem coherency. This implementation no longer permits it.