.\" Hey Emacs! This file is -*- nroff -*- source. .\" .\" This manpage is Copyright (C) 1992 Drew Eckhardt; .\" 1993 Michael Haardt, Ian Jackson. .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" Modified 1993-07-23 by Rik Faith .\" Modified 1994-08-21 by Michael Haardt .\" Modified 2004-06-23 by Michael Kerrisk .\" Modified 2005-04-04, as per suggestion by Michael Hardt for rename.2 .\" .TH LINK 2 2012-10-16 "Linux" "Linux Programmer's Manual" .SH NAME link \- make a new name for a file .SH SYNOPSIS .B #include .sp .BI "int link(const char *" oldpath ", const char *" newpath ); .SH DESCRIPTION .BR link () creates a new link (also known as a hard link) to an existing file. If .I newpath exists it will .I not be overwritten. This new name may be used exactly as the old one for any operation; both names refer to the same file (and so have the same permissions and ownership) and it is impossible to tell which name was the "original". .SH "RETURN VALUE" On success, zero is returned. On error, \-1 is returned, and .I errno is set appropriately. .SH ERRORS .TP .B EACCES Write access to the directory containing .I newpath is denied, or search permission is denied for one of the directories in the path prefix of .I oldpath or .IR newpath . (See also .BR path_resolution (7).) .TP .B EEXIST .I newpath already exists. .TP .B EFAULT .IR oldpath " or " newpath " points outside your accessible address space." .TP .B EIO An I/O error occurred. .TP .B ELOOP Too many symbolic links were encountered in resolving .IR oldpath " or " newpath . .TP .B EMLINK The file referred to by .I oldpath already has the maximum number of links to it. .TP .B ENAMETOOLONG .IR oldpath " or " newpath " was too long." .TP .B ENOENT A directory component in .IR oldpath " or " newpath does not exist or is a dangling symbolic link. .TP .B ENOMEM Insufficient kernel memory was available. .TP .B ENOSPC The device containing the file has no room for the new directory entry. .TP .B ENOTDIR A component used as a directory in .IR oldpath " or " newpath is not, in fact, a directory. .TP .B EPERM .I oldpath is a directory. .TP .B EPERM The file system containing .IR oldpath " and " newpath does not support the creation of hard links. .TP .BR EPERM " (since Linux 3.6)" The caller does not have permission to create a hard link to this file (see the description of .IR /proc/sys/fs/protected_hardlink in .BR proc (5)). .TP .B EROFS The file is on a read-only file system. .TP .B EXDEV .IR oldpath " and " newpath are not on the same mounted file system. (Linux permits a file system to be mounted at multiple points, but .BR link () does not work across different mount points, even if the same file system is mounted on both.) .SH "CONFORMING TO" SVr4, 4.3BSD, POSIX.1-2001 (but see NOTES). .\" SVr4 documents additional ENOLINK and .\" EMULTIHOP error conditions; POSIX.1 does not document ELOOP. .\" X/OPEN does not document EFAULT, ENOMEM or EIO. .SH NOTES Hard links, as created by .BR link (), cannot span file systems. Use .BR symlink (2) if this is required. POSIX.1-2001 says that .BR link () should dereference .I oldpath if it is a symbolic link. However, since kernel 2.0, .\" more precisely: since kernel 1.3.56 Linux does not do so: if .I oldpath is a symbolic link, then .I newpath is created as a (hard) link to the same symbolic link file (i.e., .I newpath becomes a symbolic link to the same file that .I oldpath refers to). Some other implementations behave in the same manner as Linux. .\" For example, the default Solaris compilation environment .\" behaves like Linux, and contributors to a March 2005 .\" thread in the Austin mailing list reported that some .\" other (System V) implementations did/do the same -- MTK, Apr 05 POSIX.1-2008 changes the specification of .BR link (), making it implementation-dependent whether or not .I oldpath is dereferenced if it is a symbolic link. For precise control over the treatment of symbolic links when creating a link, see .BR linkat (2). .SH BUGS On NFS file systems, the return code may be wrong in case the NFS server performs the link creation and dies before it can say so. Use .BR stat (2) to find out if the link got created. .SH "SEE ALSO" .BR ln (1), .BR linkat (2), .BR open (2), .BR rename (2), .BR stat (2), .BR symlink (2), .BR unlink (2), .BR path_resolution (7), .BR symlink (7) .SH COLOPHON This page is part of release 3.44 of the Linux .I man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.