LINK(2)

NAME
link - make a new name for a file

SYNOPSIS
#include <unistd.h>

int link(const char *oldpath, const char *newpath);

DESCRIPTION
link creates a new link (also known as a hard link) to an existing file. If newpath exists it will 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'.

RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

ERRORS

EXDEV
    oldpath and newpath are not on the same filesystem.

EPERM
    The filesystem containing oldpath and newpath does not support the creation of hard links.

EFAULT
    oldpath or newpath points outside your accessible address space.

EACCES
    Write access to the directory containing newpath is not allowed for the process's effective uid, or one of the directories in oldpath or newpath did not allow search (execute) permission.

ENAMETOOLONG
    oldpath or newpath was too long.

ENOENT
    A directory component in oldpath or newpath does not exist or is a dangling symbolic link.

ENOTDIR
    A component used as a directory in oldpath or newpath is not, in fact, a directory.

ENOMEM
    Insufficient kernel memory was available.

EROFS
    The file is on a read-only filesystem.

EEXIST
    newpath already exists.

EMLINK
    The file referred to by oldpath already has the maximum number of links to it.

ELOOP
    Too many symbolic links were encountered in resolving oldpath or newpath.

ENOSPC
    The device containing the file has no room for the new directory entry.

EPERM
    oldpath is a directory.

EIO An I/O error occurred.

NOTES
Hard links, as created by link, cannot span filesystems. Use symlink if this is required.

CONFORMING TO
SVr4, SVID, POSIX, BSD 4.3, X/OPEN. SVr4 documents additional ENOLINK and EMULTIHOP error conditions; POSIX.1 does not document ELOOP. X/OPEN does not document EFAULT, ENOMEM or EIO.

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 stat(2) to find out if the link got created.

SEE ALSO
symlink(2), unlink(2), rename(2), open(2), stat(2), ln(1)