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28 .\" @(#)link.2 8.3 (Berkeley) 1/12/94
37 .Nd make a hard file link
43 .Fn link "const char *name1" "const char *name2"
46 .Fa "int fd1" "const char *name1" "int fd2" "const char *name2" "int flag"
52 atomically creates the specified directory entry (hard link)
54 with the attributes of the underlying object pointed at by
56 If the link is successful: the link count of the underlying object
61 share equal access and rights
69 is not deleted and the link count of the
73 The object pointed at by the
76 must exist for the hard link to
82 must be in the same file system.
86 may not be a directory.
90 system call is equivalent to
92 except in the case where either
96 or both are relative paths.
97 In this case a relative path
99 is interpreted relative to
100 the directory associated with the file descriptor
102 instead of the current working directory and similarly for
104 and the file descriptor
109 are constructed by a bitwise-inclusive OR of flags from the following
112 .Bl -tag -width indent
113 .It Dv AT_SYMLINK_FOLLOW
116 names a symbolic link, a new link for the target of the symbolic link is
118 .It Dv AT_RESOLVE_BENEATH
119 Only walk paths below the directory specified by the
122 See the description of the
123 .Dv O_RESOLVE_BENEATH
130 argument is an empty string, link the file referenced by the descriptor
132 The operation requires that the calling process has the
134 privilege, effectively being executed with effective user
140 is passed the special value
146 parameter, the current working directory is used for the respective
155 the behavior is identical to a call to
160 .Dv AT_SYMLINK_FOLLOW
163 names a symbolic link, a new link is created for the symbolic link
172 will fail and no link will be created if:
175 A component of either path prefix is not a directory.
176 .It Bq Er ENAMETOOLONG
177 A component of either pathname exceeded 255 characters,
178 or entire length of either path name exceeded 1023 characters.
180 A component of either path prefix does not exist.
182 The file system containing the file named by
184 does not support links.
186 The link count of the file named by
190 A component of either path prefix denies search permission.
192 The requested link requires writing in a directory with a mode
193 that denies write permission.
195 Too many symbolic links were encountered in translating one of the pathnames.
211 has its immutable or append-only flag set, see the
213 manual page for more information.
215 The parent directory of the file named by
217 has its immutable flag set.
221 and the file named by
223 are on different file systems.
225 The directory in which the entry for the new link is being placed
226 cannot be extended because there is no space left on the file
227 system containing the directory.
229 The directory in which the entry for the new link
230 is being placed cannot be extended because the
231 user's quota of disk blocks on the file system
232 containing the directory has been exhausted.
234 An I/O error occurred while reading from or writing to
235 the file system to make the directory entry.
237 Corrupted data was detected while reading from the file system.
239 The requested link requires writing in a directory on a read-only file
242 One of the pathnames specified
243 is outside the process's allocated address space.
246 In addition to the errors returned by the
250 system call may fail if:
257 argument does not specify an absolute path and the
261 argument, respectively, is neither
263 nor a valid file descriptor open for searching.
267 argument is not valid.
273 argument is not an absolute path and
277 respectively, is neither
279 nor a file descriptor associated with a directory.
280 .It Bq Er ENOTCAPABLE
282 is not strictly relative to the starting directory.
285 is absolute or includes a ".." component that escapes
286 the directory hierarchy specified by
288 and the process is in capability mode or the
289 .Dv AT_RESOLVE_BENEATH
300 system call is expected to conform to
304 system call follows The Open Group Extended API Set 2 specification.
312 system call appeared in
317 system call traditionally allows the super-user to link directories which
318 corrupts the file system coherency.
319 This implementation no longer permits it.