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32 .\" @(#)fts.3 8.5 (Berkeley) 4/16/94
33 .\" $FreeBSD: src/lib/libc/gen/fts.3,v 1.7.2.6 2003/03/13 18:05:37 trhodes Exp $
34 .\" $DragonFly: src/lib/libc/gen/fts.3,v 1.4 2007/07/30 22:11:32 swildner Exp $
36 .Dd September 15, 2002
41 .Nd traverse a file hierarchy
49 .Fn fts_open "char * const *path_argv" "int options" "int (*compar)(const FTSENT **, const FTSENT **)"
51 .Fn fts_read "FTS *ftsp"
53 .Fn fts_children "FTS *ftsp" "int options"
55 .Fn fts_set "FTS *ftsp" "FTSENT *f" "int options"
57 .Fn fts_close "FTS *ftsp"
61 functions are provided for traversing
64 A simple overview is that the
68 on a file hierarchy, which is then supplied to
74 returns a pointer to a structure describing one of the files in the file
78 returns a pointer to a linked list of structures, each of which describes
79 one of the files contained in a directory in the hierarchy.
80 In general, directories are visited two distinguishable times; in pre-order
81 (before any of their descendants are visited) and in post-order (after all
82 of their descendants have been visited).
83 Files are visited once.
84 It is possible to walk the hierarchy
86 (ignoring symbolic links)
87 or physically (visiting symbolic links), order the walk of the hierarchy or
88 prune and/or re-visit portions of the hierarchy.
90 Two structures are defined (and typedef'd) in the include file
94 the structure that represents the file hierarchy itself.
97 the structure that represents a file in the file
101 structure is returned for every file in the file
106 .Dq Fa FTSENT No structure
111 structure contains at least the following fields, which are
112 described in greater detail below:
114 typedef struct _ftsent {
115 u_short fts_info; /* flags for FTSENT structure */
116 char *fts_accpath; /* access path */
117 char *fts_path; /* root path */
118 u_short fts_pathlen; /* strlen(fts_path) */
119 char *fts_name; /* file name */
120 u_short fts_namelen; /* strlen(fts_name) */
121 short fts_level; /* depth (\-1 to N) */
122 int fts_errno; /* file errno */
123 long fts_number; /* local numeric value */
124 void *fts_pointer; /* local address value */
125 struct ftsent *fts_parent; /* parent directory */
126 struct ftsent *fts_link; /* next file structure */
127 struct ftsent *fts_cycle; /* cycle structure */
128 struct stat *fts_statp; /* stat(2) information */
132 These fields are defined as follows:
133 .Bl -tag -width "fts_namelen"
135 One of the following values describing the returned
138 the file it represents.
139 With the exception of directories without errors
142 entries are terminal, that is, they will not be revisited, nor will any
143 of their descendants be visited.
144 .Bl -tag -width FTS_DEFAULT
146 A directory being visited in pre-order.
148 A directory that causes a cycle in the tree.
153 structure will be filled in as well.)
157 structure that represents a file type not explicitly described
162 A directory which cannot be read.
163 This is an error return, and the
165 field will be set to indicate what caused the error.
171 which was not specified as a file name to
176 A directory being visited in post-order.
179 structure will be unchanged from when
180 it was returned in pre-order, i.e. with the
185 This is an error return, and the
187 field will be set to indicate what caused the error.
193 information was available.
197 This is an error return, and the
199 field will be set to indicate what caused the error.
203 information was requested.
210 A symbolic link with a non-existent target.
213 field reference the file characteristic information for the symbolic link
217 A path for accessing the file from the current directory.
219 The path for the file relative to the root of the traversal.
220 This path contains the path specified to
224 The length of the string referenced by
227 The name of the file.
229 The length of the string referenced by
232 The depth of the traversal, numbered from \-1 to N, where this file
236 structure representing the parent of the starting point (or root)
237 of the traversal is numbered
238 .Dv FTS_ROOTPARENTLEVEL
241 structure for the root
261 field contains the value of the external variable
263 specifying the cause of the error.
264 Otherwise, the contents of the
268 This field is provided for the use of the application program and is
272 It is initialized to 0.
274 This field is provided for the use of the application program and is
283 structure referencing the file in the hierarchy
284 immediately above the current file, i.e. the directory of which this
286 A parent structure for the initial entry point is provided as well,
292 fields are guaranteed to be initialized.
298 field points to the next structure in the NULL-terminated linked list of
300 Otherwise, the contents of the
304 If a directory causes a cycle in the hierarchy (see
307 of a hard link between two directories, or a symbolic link pointing to a
310 field of the structure will point to the
312 structure in the hierarchy that references the same file as the current
315 Otherwise, the contents of the
321 information for the file.
324 A single buffer is used for all of the paths of all of the files in the
330 fields are guaranteed to be
331 .Dv NUL Ns -terminated
333 for the file most recently returned by
335 To use these fields to reference any files represented by other
337 structures will require that the path buffer be modified using the
338 information contained in that
343 Any such modifications should be undone before further calls to
349 .Dv NUL Ns -terminated .
353 function takes a pointer to an array of character pointers naming one
354 or more paths which make up a logical file hierarchy to be traversed.
355 The array must be terminated by a
360 a number of options, at least one of which (either
365 The options are selected by
367 the following values:
368 .Bl -tag -width "FTS_PHYSICAL"
370 This option causes any symbolic link specified as a root path to be
371 followed immediately whether or not
375 This option causes the
379 structures for the targets of symbolic links
380 instead of the symbolic links themselves.
381 If this option is set, the only symbolic links for which
384 are returned to the application are those referencing non-existent files.
394 As a performance optimization, the
396 functions change directories as they walk the file hierarchy.
397 This has the side-effect that an application cannot rely on being
398 in any particular directory during the traversal.
401 option turns off this optimization, and the
403 functions will not change the current directory.
404 Note that applications should not themselves change their current directory
405 and try to access files unless
407 is specified and absolute
408 pathnames were provided as arguments to
413 structures reference file characteristic information (the
415 field) for each file visited.
416 This option relaxes that requirement as a performance optimization,
423 and leave the contents of the
427 This option causes the
431 structures for symbolic links themselves instead
432 of the target files they point to.
433 If this option is set,
435 structures for all symbolic links in the
436 hierarchy are returned to the application.
446 By default, unless they are specified as path arguments to
452 encountered in the file hierarchy are ignored.
453 This option causes the
461 from descending into directories that have a different device number
462 than the file from which the descent began.
467 specifies a user-defined function which may be used to order the traversal
470 takes two pointers to pointers to
472 structures as arguments and
473 should return a negative value, zero, or a positive value to indicate
474 if the file referenced by its first argument comes before, in any order
475 with respect to, or after, the file referenced by its second argument.
485 be used in this comparison.
494 field may not either.
499 the directory traversal order is in the order listed in
501 for the root paths, and in the order listed in the directory for
506 function returns a pointer to an
508 structure describing a file in
510 Directories (that are readable and do not cause cycles) are visited at
511 least twice, once in pre-order and once in post-order.
512 All other files are visited at least once.
513 (Hard links between directories that do not cause cycles or symbolic
514 links to symbolic links may cause files to be visited more than once,
515 or directories more than twice.)
517 If all the members of the hierarchy have been returned,
521 and sets the external variable
524 If an error unrelated to a file in the hierarchy occurs,
531 If an error related to a returned file occurs, a pointer to an
533 structure is returned, and
535 may or may not have been set (see
540 structures returned by
542 may be overwritten after a call to
544 on the same file hierarchy stream, or, after a call to
546 on the same file hierarchy stream unless they represent a file of type
547 directory, in which case they will not be overwritten until after a call to
551 structure has been returned by the function
557 function returns a pointer to an
559 structure describing the first entry in a NULL-terminated linked list of
560 the files in the directory represented by the
562 structure most recently returned by
564 The list is linked through the
568 structure, and is ordered by the user-specified comparison function, if any.
571 will recreate this linked list.
573 As a special case, if
575 has not yet been called for a hierarchy,
577 will return a pointer to the files in the logical directory specified to
579 i.e. the arguments specified to
583 structure most recently returned by
585 is not a directory being visited in pre-order,
586 or the directory does not contain any files,
603 structures returned by
605 may be overwritten after a call to
610 on the same file hierarchy stream.
613 may be set to the following value:
614 .Bl -tag -width FTS_NAMEONLY
616 Only the names of the files are needed.
617 The contents of all the fields in the returned linked list of structures
618 are undefined with the exception of the
627 allows the user application to determine further processing for the
635 returns 0 on success, and \-1 if an error occurs.
637 must be set to one of the following values:
638 .Bl -tag -width FTS_PHYSICAL
640 Re-visit the file; any file type may be re-visited.
643 will return the referenced file.
648 fields of the structure will be reinitialized at that time,
649 but no other fields will have been changed.
650 This option is meaningful only for the most recently returned
653 Normal use is for post-order directory visits, where it causes the
654 directory to be re-visited (in both pre and post-order) as well as all
657 The referenced file must be a symbolic link.
658 If the referenced file is the one most recently returned by
662 returns the file with the
666 fields reinitialized to reflect the target of the symbolic link instead
667 of the symbolic link itself.
668 If the file is one of those most recently returned by
674 fields of the structure, when returned by
676 will reflect the target of the symbolic link instead of the symbolic link
678 In either case, if the target of the symbolic link does not exist the
679 fields of the returned structure will be unchanged and the
684 If the target of the link is a directory, the pre-order return, followed
685 by the return of all of its descendants, followed by a post-order return,
688 No descendants of this file are visited.
689 The file may be one of those most recently returned by either
697 function closes a file hierarchy stream
699 and restores the current directory to the directory from which
706 returns 0 on success, and \-1 if an error occurs.
712 for any of the errors specified for the library functions
721 for any of the errors specified for the library functions
732 for any of the errors specified for the library functions
750 The options were invalid.
760 utility is expected to be included in a future