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FreeBSD man pages : link (2)
LINK(2) 		  FreeBSD System Calls Manual		       LINK(2)

NAME

link - make a hard file link

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <unistd.h> int link(const char *name1, const char *name2);

DESCRIPTION

The link() function call atomically creates the specified directory entry (hard link) name2 with the attributes of the underlying object pointed at by name1. If the link is successful: the link count of the underlying object is incremented; name1 and name2 share equal access and rights to the underlying object. If name1 is removed, the file name2 is not deleted and the link count of the underlying object is decremented. Name1 must exist for the hard link to succeed and both name1 and name2 must be in the same file system. name1 may not be a directory.

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

Link() will fail and no link will be created if: [ENOTDIR] A component of either path prefix is not a directory. [ENAMETOOLONG] A component of either pathname exceeded 255 charac- ters, or entire length of either path name exceeded 1023 characters. [ENOENT] A component of either path prefix does not exist. [EOPNOTSUPP] The file system containing the file named by name1 does not support links. [EMLINK] The link count of the file named by name1 would exceed 32767. [EACCES] A component of either path prefix denies search per- mission. [EACCES] The requested link requires writing in a directory with a mode that denies write permission. [ELOOP] Too many symbolic links were encountered in translat- ing one of the pathnames. [ENOENT] The file named by name1 does not exist. [EEXIST] The link named by name2 does exist. [EPERM] The file named by name1 is a directory. [EXDEV] The link named by name2 and the file named by name1 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 direc- tory. [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. [EROFS] The requested link requires writing in a directory on a read-only file system. [EFAULT] One of the pathnames specified is outside the pro- cess's allocated address space.

SEE ALSO

readlink(2), symlink(2), unlink(2)

STANDARDS

The link() function call is expected to conform to ISO/IEC 9945-1:1990 (``POSIX.1'').

HISTORY

A link() function call appeared in Version 7 AT&T UNIX. The link() system call traditionally allows the super-user to link direc- tories which corrupts the filesystem coherency. This implementation no longer permits it. FreeBSD 4.8 March 5, 1999 FreeBSD 4.8