1 .\" Copyright (c) 1993 Michael Haardt (michael@moria.de)
2 .\" and copyright (c) 1999 Andries Brouwer (aeb@cwi.nl)
3 .\" and copyright (c) 2006 Justin Pryzby <justinpryzby@users.sf.net>
4 .\" and copyright (c) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
6 .\" This is free documentation; you can redistribute it and/or
7 .\" modify it under the terms of the GNU General Public License as
8 .\" published by the Free Software Foundation; either version 2 of
9 .\" the License, or (at your option) any later version.
11 .\" The GNU General Public License's references to "object code"
12 .\" and "executables" are to be interpreted as the output of any
13 .\" document formatting or typesetting system, including
14 .\" intermediate and printed output.
16 .\" This manual is distributed in the hope that it will be useful,
17 .\" but WITHOUT ANY WARRANTY; without even the implied warranty of
18 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 .\" GNU General Public License for more details.
21 .\" You should have received a copy of the GNU General Public
22 .\" License along with this manual; if not, write to the Free
23 .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
26 .\" Modified Sun Jul 25 11:02:22 1993 by Rik Faith (faith@cs.unc.edu)
27 .\" 2006-05-24, Justin Pryzby <justinpryzby@users.sf.net>
28 .\" document FTW_ACTIONRETVAL; include .SH "RETURN VALUE";
29 .\" 2006-05-24, Justin Pryzby <justinpryzby@users.sf.net> and
30 .\" Michael Kerrisk <mtk.manpages@gmail.com>
31 .\" reorganized and rewrote much of the page
32 .\" 2006-05-24, Michael Kerrisk <mtk.manpages@gmail.com>
33 .\" Added an example program.
34 .TH FTW 3 2007-07-26 "Linux" "Linux Programmer's Manual"
36 ftw, nftw \- file tree walk
41 .BI "int ftw(const char *" dirpath ,
42 .BI " int (*" fn ") (const char *" fpath ", const struct stat *" sb ,
43 .BI " int " typeflag ),
44 .BI " int " nopenfd );
46 .B #define _XOPEN_SOURCE 500
49 .BI "int nftw(const char *" dirpath ,
50 .BI " int (*" fn ") (const char *" fpath ", const struct stat *" sb ,
51 .BI " int " typeflag ", struct FTW *" ftwbuf ),
52 .BI " int " nopenfd ", int " flags );
56 walks through the directory tree that is
57 located under the directory \fIdirpath\fP,
58 and calls \fIfn\fP() once for each entry in the tree.
59 By default, directories are handled before the files and
60 subdirectories they contain (pre-order traversal).
62 To avoid using up all of the calling process's file descriptors,
63 \fInopenfd\fP specifies the maximum number of directories that
65 will hold open simultaneously.
67 the search depth exceeds this,
69 will become slower because
70 directories have to be closed and reopened.
73 one file descriptor for each level in the directory tree.
75 For each entry found in the tree,
78 \fIfn\fP() with three arguments:
84 is the pathname of the entry relative to
89 structure returned by a call to
94 is an integer that has one of the following values:
106 is a directory which can't be read.
113 which is not a symbolic link.
117 is a symbolic link and
119 failed, POSIX.1-2001 states
120 that it is undefined whether \fBFTW_NS\fP or \fBFTW_SL\fP (see below)
124 To stop the tree walk, \fIfn\fP() returns a non-zero value; this
125 value will become the return value of
127 As long as \fIfn\fP() returns 0,
129 will continue either until it has traversed the entire tree,
130 in which case it will return zero,
131 or until it encounters an error (such as a
133 failure), in which case it will return \-1.
137 uses dynamic data structures, the only safe way to
138 exit out of a tree walk is to return a non-zero value from \fIfn\fP().
139 To allow a signal to terminate the walk without causing a memory leak,
140 have the handler set a global flag that is checked by \fIfn\fP().
143 unless the program is going to terminate.
149 except that it has one additional argument, \fIflags\fP,
150 and calls \fIfn\fP() with one more argument, \fIftwbuf\fP.
152 This \fIflags\fP argument is formed by ORing zero or more of the
155 .BR FTW_ACTIONRETVAL " (since glibc 2.3.3)"
156 If this glibc-specific flag is set, then
158 handles the return value from
162 should return one of the following values:
168 to continue normally.
171 If \fIfn\fP() returns this value, then
172 siblings of the current entry will be skipped,
173 and processing continues in the parent.
174 .\" If \fBFTW_DEPTH\fP
175 .\" is set, the entry's parent directory is processed next (with
176 .\" \fIflag\fP set to \fBFTW_DP\fP).
179 If \fIfn\fP() is called with an entry that is a directory
180 (\fItypeflag\fP is \fBFTW_D\fP), this return
181 value will prevent objects within that directory from being passed as
182 arguments to \fIfn\fP().
184 continues processing with the next sibling of the directory.
189 to return immediately with the return value
192 Other return values could be associated with new actions in the future;
193 \fIfn\fP() should not return values other than those listed above.
195 The feature test macro
197 must be defined in order to
198 obtain the definition of \fBFTW_ACTIONRETVAL\fP from \fI<ftw.h>\fP.
204 to each directory before handling its contents.
205 This is useful if the program needs to perform some action
206 in the directory in which \fIfpath\fP resides.
209 If set, do a post-order traversal, that is, call \fIfn\fP() for
210 the directory itself \fIafter\fP handling the contents of the directory
211 and its subdirectories.
212 (By default, each directory is handled \fIbefore\fP its contents.)
215 If set, stay within the same file system
216 (i.e., do not cross mount points).
219 If set, do not follow symbolic links.
220 (This is what you want.)
221 If not set, symbolic links are followed, but no file is reported twice.
223 If \fBFTW_PHYS\fP is not set, but \fBFTW_DEPTH\fP is set,
226 is never called for a directory that would be a descendant of itself.
228 For each entry in the directory tree,
239 may receive any of the same values as with
241 or any of the following values:
245 is a directory, and \fBFTW_DEPTH\fP was specified in \fIflags\fP.
247 and subdirectories within \fIfpath\fP have been processed.
251 is a symbolic link, and \fBFTW_PHYS\fP was set in \fIflags\fP.
252 .\" To obtain the definition of this constant from
256 .\" must be defined, or
257 .\" .BR _XOPEN_SOURCE
258 .\" must be defined with a value of 500 or more.
262 is a symbolic link pointing to a nonexistent file.
263 (This occurs only if \fBFTW_PHYS\fP is not set.)
265 The fourth argument that
267 supplies when calling
269 is a structure of type \fIFTW\fP:
281 is the offset of the filename (i.e., basename component)
282 in the pathname given in
287 in the directory tree, relative to the root of the tree
291 These functions return 0 on success, and \-1 if an error occurs.
293 If \fIfn\fP() returns non-zero,
294 then the tree walk is terminated and the value returned by \fIfn\fP()
295 is returned as the result of
302 is called with the \fBFTW_ACTIONRETVAL\fP flag,
303 then the only non-zero value that should be used by \fIfn\fP()
304 to terminate the tree walk is \fBFTW_STOP\fP,
305 and that value is returned as the result of
308 POSIX.1-2001, SVr4, SUSv1.
312 and the use of \fBFTW_SL\fP with
314 were introduced in SUSv1.
318 will never use \fBFTW_SL\fP, on other systems \fBFTW_SL\fP occurs only
319 for symbolic links that do not point to an existing file,
320 and again on other systems
322 will use \fBFTW_SL\fP for each symbolic link.
323 For predictable control, use
326 Under Linux, libc4 and libc5 and glibc 2.0.6 will
327 use \fBFTW_F\fP for all objects (files, symbolic links, fifos, etc.)
328 that can be stat'ed but are not a directory.
332 is available since glibc 2.1.
334 \fBFTW_ACTIONRETVAL\fP is glibc specific.
336 The following program traverses the directory tree under the path named
337 in its first command-line argument, or under the current directory
338 if no argument is supplied.
339 It displays various information about each file.
340 The second-command line argument can be used to specify characters that
341 control the value assigned to the \fIflags\fP
342 argument when calling
346 #define _XOPEN_SOURCE 500
354 display_info(const char *fpath, const struct stat *sb,
355 int tflag, struct FTW *ftwbuf)
357 printf("%\-3s %2d %7jd %\-40s %d %s\\n",
358 (tflag == FTW_D) ? "d" : (tflag == FTW_DNR) ? "dnr" :
359 (tflag == FTW_DP) ? "dp" : (tflag == FTW_F) ? "f" :
360 (tflag == FTW_NS) ? "ns" : (tflag == FTW_SL) ? "sl" :
361 (tflag == FTW_SLN) ? "sln" : "???",
362 ftwbuf\->level, (intmax_t) sb\->st_size,
363 fpath, ftwbuf\->base, fpath + ftwbuf\->base);
364 return 0; /* To tell nftw() to continue */
368 main(int argc, char *argv[])
372 if (argc > 2 && strchr(argv[2], 'd') != NULL)
374 if (argc > 2 && strchr(argv[2], 'p') != NULL)
377 if (nftw((argc < 2) ? "." : argv[1], display_info, 20, flags)
389 .BR feature_test_macros (7)