link - make a new name for a file
int link(const char *oldpath, const char *newpath));
link creates a new link (also known as a hard link) to an
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'.
On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
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
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.
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 max-
imum number of links to it.
ELOOP Too many symbolic links were encountered in resolv-
ing 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.
Hard links, as created by link, cannot span filesystems. Use
symlink if this is required.
SVr4, SVID, POSIX, BSD 4.3, X/OPEN. SVr4 documents addi-
tional ENOLINK and EMULTIHOP error conditions; POSIX.1 does
not document ELOOP. X/OPEN does not document EFAULT, ENOMEM
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
symlink(2), unlink(2), rename(2), open(2), stat(2), ln(1)