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32 .\" @(#)fts.3 8.5 (Berkeley) 4/16/94
40 .Nd traverse a file hierarchy
42 .Fd #include <sys/types.h>
43 .Fd #include <sys/stat.h>
46 .Fn fts_open "char * const *path_argv" "int options" "int (*compar)(const FTSENT **, const FTSENT **)"
48 .Fn fts_read "FTS *ftsp"
50 .Fn fts_children "FTS *ftsp" "int options"
52 .Fn fts_set "FTS *ftsp" "FTSENT *f" "int options"
54 .Fn fts_close "FTS *ftsp"
58 functions are provided for traversing
61 A simple overview is that the
65 on a file hierarchy, which is then supplied to
71 returns a pointer to a structure describing one of the files in the file
75 returns a pointer to a linked list of structures, each of which describes
76 one of the files contained in a directory in the hierarchy.
77 In general, directories are visited two distinguishable times; in pre-order
78 (before any of their descendants are visited) and in post-order (after all
79 of their descendants have been visited).
80 Files are visited once.
81 It is possible to walk the hierarchy
83 (ignoring symbolic links)
84 or physically (visiting symbolic links), order the walk of the hierarchy or
85 prune and/or re-visit portions of the hierarchy.
87 Two structures are defined (and typedef'd) in the include file
91 the structure that represents the file hierarchy itself.
94 the structure that represents a file in the file
98 structure is returned for every file in the file
103 .Dq Fa FTSENT No structure
108 structure contains at least the following fields, which are
109 described in greater detail below:
111 typedef struct _ftsent {
112 u_short fts_info; /* flags for FTSENT structure */
113 char *fts_accpath; /* access path */
114 char *fts_path; /* root path */
115 u_short fts_pathlen; /* strlen(fts_path) */
116 char *fts_name; /* file name */
117 u_short fts_namelen; /* strlen(fts_name) */
118 short fts_level; /* depth (\-1 to N) */
119 int fts_errno; /* file errno */
120 long fts_number; /* local numeric value */
121 void *fts_pointer; /* local address value */
122 struct ftsent *fts_parent; /* parent directory */
123 struct ftsent *fts_link; /* next file structure */
124 struct ftsent *fts_cycle; /* cycle structure */
125 struct stat *fts_statp; /* stat(2) information */
129 These fields are defined as follows:
130 .Bl -tag -width "fts_namelen"
132 One of the following values describing the returned
135 the file it represents.
136 With the exception of directories without errors
139 entries are terminal, that is, they will not be revisited, nor will any
140 of their descendants be visited.
141 .Bl -tag -width FTS_DEFAULT
143 A directory being visited in pre-order.
145 A directory that causes a cycle in the tree.
150 structure will be filled in as well.)
154 structure that represents a file type not explicitly described
159 A directory which cannot be read.
160 This is an error return, and the
162 field will be set to indicate what caused the error.
168 which was not specified as a file name to
173 A directory being visited in post-order.
176 structure will be unchanged from when
177 it was returned in pre-order, i.e. with the
182 This is an error return, and the
184 field will be set to indicate what caused the error.
190 information was available.
194 This is an error return, and the
196 field will be set to indicate what caused the error.
200 information was requested.
207 A symbolic link with a non-existent target.
210 field reference the file characteristic information for the symbolic link
214 A path for accessing the file from the current directory.
216 The path for the file relative to the root of the traversal.
217 This path contains the path specified to
221 The length of the string referenced by
224 The name of the file.
226 The length of the string referenced by
229 The depth of the traversal, numbered from \-1 to N, where this file
233 structure representing the parent of the starting point (or root)
234 of the traversal is numbered \-1, and the
236 structure for the root
237 itself is numbered 0.
254 field contains the value of the external variable
256 specifying the cause of the error.
257 Otherwise, the contents of the
261 This field is provided for the use of the application program and is
265 It is initialized to 0.
267 This field is provided for the use of the application program and is
276 structure referencing the file in the hierarchy
277 immediately above the current file, i.e. the directory of which this
279 A parent structure for the initial entry point is provided as well,
285 fields are guaranteed to be initialized.
291 field points to the next structure in the NULL-terminated linked list of
293 Otherwise, the contents of the
297 If a directory causes a cycle in the hierarchy (see
300 of a hard link between two directories, or a symbolic link pointing to a
303 field of the structure will point to the
305 structure in the hierarchy that references the same file as the current
308 Otherwise, the contents of the
314 information for the file.
317 A single buffer is used for all of the paths of all of the files in the
323 fields are guaranteed to be
324 .Dv NUL Ns -terminated
326 for the file most recently returned by
328 To use these fields to reference any files represented by other
330 structures will require that the path buffer be modified using the
331 information contained in that
336 Any such modifications should be undone before further calls to
342 .Dv NUL Ns -terminated.
346 function takes a pointer to an array of character pointers naming one
347 or more paths which make up a logical file hierarchy to be traversed.
348 The array must be terminated by a
353 a number of options, at least one of which (either
358 The options are selected by
360 the following values:
361 .Bl -tag -width "FTS_PHYSICAL"
363 This option causes any symbolic link specified as a root path to be
364 followed immediately whether or not
368 This option causes the
372 structures for the targets of symbolic links
373 instead of the symbolic links themselves.
374 If this option is set, the only symbolic links for which
377 are returned to the application are those referencing non-existent files.
387 As a performance optimization, the
389 functions change directories as they walk the file hierarchy.
390 This has the side-effect that an application cannot rely on being
391 in any particular directory during the traversal.
394 option turns off this optimization, and the
396 functions will not change the current directory.
397 Note that applications should not themselves change their current directory
398 and try to access files unless
400 is specified and absolute
401 pathnames were provided as arguments to
406 structures reference file characteristic information (the
408 field) for each file visited.
409 This option relaxes that requirement as a performance optimization,
416 and leave the contents of the
420 This option causes the
424 structures for symbolic links themselves instead
425 of the target files they point to.
426 If this option is set,
428 structures for all symbolic links in the
429 hierarchy are returned to the application.
439 By default, unless they are specified as path arguments to
445 encountered in the file hierarchy are ignored.
446 This option causes the
454 from descending into directories that have a different device number
455 than the file from which the descent began.
460 specifies a user-defined function which may be used to order the traversal
463 takes two pointers to pointers to
465 structures as arguments and
466 should return a negative value, zero, or a positive value to indicate
467 if the file referenced by its first argument comes before, in any order
468 with respect to, or after, the file referenced by its second argument.
478 be used in this comparison.
487 field may not either.
492 the directory traversal order is in the order listed in
494 for the root paths, and in the order listed in the directory for
499 function returns a pointer to an
501 structure describing a file in
503 Directories (that are readable and do not cause cycles) are visited at
504 least twice, once in pre-order and once in post-order.
505 All other files are visited at least once.
506 (Hard links between directories that do not cause cycles or symbolic
507 links to symbolic links may cause files to be visited more than once,
508 or directories more than twice.)
510 If all the members of the hierarchy have been returned,
514 and sets the external variable
517 If an error unrelated to a file in the hierarchy occurs,
524 If an error related to a returned file occurs, a pointer to an
526 structure is returned, and
528 may or may not have been set (see
533 structures returned by
535 may be overwritten after a call to
537 on the same file hierarchy stream, or, after a call to
539 on the same file hierarchy stream unless they represent a file of type
540 directory, in which case they will not be overwritten until after a call to
544 structure has been returned by the function
550 function returns a pointer to an
552 structure describing the first entry in a NULL-terminated linked list of
553 the files in the directory represented by the
555 structure most recently returned by
557 The list is linked through the
561 structure, and is ordered by the user-specified comparison function, if any.
564 will recreate this linked list.
566 As a special case, if
568 has not yet been called for a hierarchy,
570 will return a pointer to the files in the logical directory specified to
572 i.e. the arguments specified to
576 structure most recently returned by
578 is not a directory being visited in pre-order,
579 or the directory does not contain any files,
596 structures returned by
598 may be overwritten after a call to
603 on the same file hierarchy stream.
606 may be set to the following value:
607 .Bl -tag -width FTS_NAMEONLY
609 Only the names of the files are needed.
610 The contents of all the fields in the returned linked list of structures
611 are undefined with the exception of the
620 allows the user application to determine further processing for the
628 returns 0 on success, and \-1 if an error occurs.
630 must be set to one of the following values:
631 .Bl -tag -width FTS_PHYSICAL
633 Re-visit the file; any file type may be re-visited.
636 will return the referenced file.
641 fields of the structure will be reinitialized at that time,
642 but no other fields will have been changed.
643 This option is meaningful only for the most recently returned
646 Normal use is for post-order directory visits, where it causes the
647 directory to be re-visited (in both pre and post-order) as well as all
650 The referenced file must be a symbolic link.
651 If the referenced file is the one most recently returned by
655 returns the file with the
659 fields reinitialized to reflect the target of the symbolic link instead
660 of the symbolic link itself.
661 If the file is one of those most recently returned by
667 fields of the structure, when returned by
669 will reflect the target of the symbolic link instead of the symbolic link
671 In either case, if the target of the symbolic link does not exist the
672 fields of the returned structure will be unchanged and the
677 If the target of the link is a directory, the pre-order return, followed
678 by the return of all of its descendants, followed by a post-order return,
681 No descendants of this file are visited.
682 The file may be one of those most recently returned by either
690 function closes a file hierarchy stream
692 and restores the current directory to the directory from which
699 returns 0 on success, and \-1 if an error occurs.
705 for any of the errors specified for the library functions
714 for any of the errors specified for the library functions
725 for any of the errors specified for the library functions
743 The options were invalid.
753 utility is expected to be included in a future