1 .\" Copyright (c) 1989, 1991, 1993, 1994
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 4. Neither the name of the University nor the names of its contributors
13 .\" may be used to endorse or promote products derived from this software
14 .\" without specific prior written permission.
16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 .\" @(#)fts.3 8.5 (Berkeley) 4/16/94
36 .Nd traverse a file hierarchy
44 .Fn fts_open "char * const *path_argv" "int options" "int (*compar)(const FTSENT * const *, const FTSENT * const *)"
46 .Fn fts_read "FTS *ftsp"
48 .Fn fts_children "FTS *ftsp" "int options"
50 .Fn fts_set "FTS *ftsp" "FTSENT *f" "int options"
52 .Fn fts_set_clientptr "FTS *ftsp" "void *clientdata"
54 .Fn fts_get_clientptr "FTS *ftsp"
56 .Fn fts_get_stream "FTSENT *f"
58 .Fn fts_close "FTS *ftsp"
62 functions are provided for traversing
65 A simple overview is that the
69 on a file hierarchy, which is then supplied to
75 returns a pointer to a structure describing one of the files in the file
79 returns a pointer to a linked list of structures, each of which describes
80 one of the files contained in a directory in the hierarchy.
81 In general, directories are visited two distinguishable times; in pre-order
82 (before any of their descendants are visited) and in post-order (after all
83 of their descendants have been visited).
84 Files are visited once.
85 It is possible to walk the hierarchy
87 (ignoring symbolic links)
88 or physically (visiting symbolic links), order the walk of the hierarchy or
89 prune and/or re-visit portions of the hierarchy.
91 Two structures are defined (and typedef'd) in the include file
95 the structure that represents the file hierarchy itself.
98 the structure that represents a file in the file
102 structure is returned for every file in the file
107 .Dq Vt FTSENT No structure
113 structure contains space for a single pointer, which may be used to
114 store application data or per-hierarchy state.
116 .Fn fts_set_clientptr
118 .Fn fts_get_clientptr
119 functions may be used to set and retrieve this pointer.
120 This is likely to be useful only when accessed from the sort
121 comparison function, which can determine the original
123 stream of its arguments using the
128 functions are also available as macros of the same name.
132 structure contains at least the following fields, which are
133 described in greater detail below:
135 typedef struct _ftsent {
136 int fts_info; /* status for FTSENT structure */
137 char *fts_accpath; /* access path */
138 char *fts_path; /* root path */
139 size_t fts_pathlen; /* strlen(fts_path) */
140 char *fts_name; /* file name */
141 size_t fts_namelen; /* strlen(fts_name) */
142 long fts_level; /* depth (\-1 to N) */
143 int fts_errno; /* file errno */
144 long long fts_number; /* local numeric value */
145 void *fts_pointer; /* local address value */
146 struct ftsent *fts_parent; /* parent directory */
147 struct ftsent *fts_link; /* next file structure */
148 struct ftsent *fts_cycle; /* cycle structure */
149 struct stat *fts_statp; /* stat(2) information */
153 These fields are defined as follows:
154 .Bl -tag -width "fts_namelen"
156 One of the following values describing the returned
159 the file it represents.
160 With the exception of directories without errors
163 entries are terminal, that is, they will not be revisited, nor will any
164 of their descendants be visited.
165 .Bl -tag -width FTS_DEFAULT
167 A directory being visited in pre-order.
169 A directory that causes a cycle in the tree.
174 structure will be filled in as well.)
178 structure that represents a file type not explicitly described
183 A directory which cannot be read.
184 This is an error return, and the
186 field will be set to indicate what caused the error.
192 which was not specified as a file name to
197 A directory being visited in post-order.
200 structure will be unchanged from when
201 it was returned in pre-order, i.e., with the
206 This is an error return, and the
208 field will be set to indicate what caused the error.
214 information was available.
218 This is an error return, and the
220 field will be set to indicate what caused the error.
224 information was requested.
231 A symbolic link with a non-existent target.
234 field reference the file characteristic information for the symbolic link
238 A path for accessing the file from the current directory.
240 The path for the file relative to the root of the traversal.
241 This path contains the path specified to
245 The length of the string referenced by
248 The name of the file.
250 The length of the string referenced by
253 The depth of the traversal, numbered from \-1 to N, where this file
257 structure representing the parent of the starting point (or root)
258 of the traversal is numbered
259 .Dv FTS_ROOTPARENTLEVEL
262 structure for the root
282 field contains the value of the external variable
284 specifying the cause of the error.
285 Otherwise, the contents of the
289 This field is provided for the use of the application program and is
293 It is initialized to 0.
295 This field is provided for the use of the application program and is
304 structure referencing the file in the hierarchy
305 immediately above the current file, i.e., the directory of which this
307 A parent structure for the initial entry point is provided as well,
314 fields are guaranteed to be initialized.
320 field points to the next structure in the NULL-terminated linked list of
322 Otherwise, the contents of the
326 If a directory causes a cycle in the hierarchy (see
329 of a hard link between two directories, or a symbolic link pointing to a
332 field of the structure will point to the
334 structure in the hierarchy that references the same file as the current
337 Otherwise, the contents of the
343 information for the file.
346 A single buffer is used for all of the paths of all of the files in the
352 fields are guaranteed to be
353 .Dv NUL Ns -terminated
355 for the file most recently returned by
357 To use these fields to reference any files represented by other
359 structures will require that the path buffer be modified using the
360 information contained in that
365 Any such modifications should be undone before further calls to
371 .Dv NUL Ns -terminated .
375 is mutually exclusive with the use of
382 function takes a pointer to an array of character pointers naming one
383 or more paths which make up a logical file hierarchy to be traversed.
384 The array must be terminated by a
389 a number of options, at least one of which (either
394 The options are selected by
396 the following values:
397 .Bl -tag -width "FTS_PHYSICAL"
399 This option causes any symbolic link specified as a root path to be
400 followed immediately whether or not
404 This option causes the
408 structures for the targets of symbolic links
409 instead of the symbolic links themselves.
410 If this option is set, the only symbolic links for which
413 are returned to the application are those referencing non-existent files.
423 As a performance optimization, the
425 functions change directories as they walk the file hierarchy.
426 This has the side-effect that an application cannot rely on being
427 in any particular directory during the traversal.
430 option turns off this optimization, and the
432 functions will not change the current directory.
433 Note that applications should not themselves change their current directory
434 and try to access files unless
436 is specified and absolute
437 pathnames were provided as arguments to
442 structures reference file characteristic information (the
444 field) for each file visited.
445 This option relaxes that requirement as a performance optimization,
452 and leave the contents of the
456 This option causes the
460 structures for symbolic links themselves instead
461 of the target files they point to.
462 If this option is set,
464 structures for all symbolic links in the
465 hierarchy are returned to the application.
475 By default, unless they are specified as path arguments to
481 encountered in the file hierarchy are ignored.
482 This option causes the
490 from descending into directories that have a different device number
491 than the file from which the descent began.
496 specifies a user-defined function which may be used to order the traversal
499 takes two pointers to pointers to
501 structures as arguments and
502 should return a negative value, zero, or a positive value to indicate
503 if the file referenced by its first argument comes before, in any order
504 with respect to, or after, the file referenced by its second argument.
514 be used in this comparison.
523 field may not either.
528 the directory traversal order is in the order listed in
530 for the root paths, and in the order listed in the directory for
535 function returns a pointer to an
537 structure describing a file in
539 Directories (that are readable and do not cause cycles) are visited at
540 least twice, once in pre-order and once in post-order.
541 All other files are visited at least once.
542 (Hard links between directories that do not cause cycles or symbolic
543 links to symbolic links may cause files to be visited more than once,
544 or directories more than twice.)
546 If all the members of the hierarchy have been returned,
550 and sets the external variable
553 If an error unrelated to a file in the hierarchy occurs,
560 If an error related to a returned file occurs, a pointer to an
562 structure is returned, and
564 may or may not have been set (see
569 structures returned by
571 may be overwritten after a call to
573 on the same file hierarchy stream, or, after a call to
575 on the same file hierarchy stream unless they represent a file of type
576 directory, in which case they will not be overwritten until after a call to
580 structure has been returned by the function
586 function returns a pointer to an
588 structure describing the first entry in a NULL-terminated linked list of
589 the files in the directory represented by the
591 structure most recently returned by
593 The list is linked through the
597 structure, and is ordered by the user-specified comparison function, if any.
600 will recreate this linked list.
602 As a special case, if
604 has not yet been called for a hierarchy,
606 will return a pointer to the files in the logical directory specified to
608 i.e., the arguments specified to
612 structure most recently returned by
614 is not a directory being visited in pre-order,
615 or the directory does not contain any files,
632 structures returned by
634 may be overwritten after a call to
639 on the same file hierarchy stream.
642 may be set to the following value:
643 .Bl -tag -width FTS_NAMEONLY
645 Only the names of the files are needed.
646 The contents of all the fields in the returned linked list of structures
647 are undefined with the exception of the
656 allows the user application to determine further processing for the
664 returns 0 on success, and \-1 if an error occurs.
666 must be set to one of the following values:
667 .Bl -tag -width FTS_PHYSICAL
669 Re-visit the file; any file type may be re-visited.
672 will return the referenced file.
677 fields of the structure will be reinitialized at that time,
678 but no other fields will have been changed.
679 This option is meaningful only for the most recently returned
682 Normal use is for post-order directory visits, where it causes the
683 directory to be re-visited (in both pre and post-order) as well as all
686 The referenced file must be a symbolic link.
687 If the referenced file is the one most recently returned by
691 returns the file with the
695 fields reinitialized to reflect the target of the symbolic link instead
696 of the symbolic link itself.
697 If the file is one of those most recently returned by
703 fields of the structure, when returned by
705 will reflect the target of the symbolic link instead of the symbolic link
707 In either case, if the target of the symbolic link does not exist the
708 fields of the returned structure will be unchanged and the
713 If the target of the link is a directory, the pre-order return, followed
714 by the return of all of its descendants, followed by a post-order return,
717 No descendants of this file are visited.
718 The file may be one of those most recently returned by either
726 function closes a file hierarchy stream
728 and restores the current directory to the directory from which
735 returns 0 on success, and \-1 if an error occurs.
741 for any of the errors specified for the library functions
750 for any of the errors specified for the library functions
761 for any of the errors specified for the library functions
779 The options were invalid.
790 interface was first introduced in
793 .Fn fts_get_clientptr ,
796 .Fn fts_set_clientptr
797 functions were introduced in
799 principally to provide for alternative interfaces to the
801 functionality using different data structures.