1.\" $OpenBSD: ftw.3,v 1.5 2004/01/25 14:48:32 jmc Exp $ 2.\" 3.\" Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.\" Sponsored in part by the Defense Advanced Research Projects 18.\" Agency (DARPA) and Air Force Research Laboratory, Air Force 19.\" Materiel Command, USAF, under agreement number F39502-99-1-0512. 20.\" 21.\" $FreeBSD: src/lib/libc/gen/ftw.3,v 1.3 2005/11/23 15:41:36 ru Exp $ 22.\" 23.Dd December 13, 2008 24.Dt FTW 3 25.Os 26.Sh NAME 27.Nm ftw , nftw 28.Nd traverse (walk) a file tree 29.Sh SYNOPSIS 30.In ftw.h 31.Ft int 32.Fo ftw 33.Fa "const char *path" 34.Fa "int \*[lp]*fn\*[rp]\*[lp]const char *, const struct stat *, int\*[rp]" 35.Fa "int maxfds" 36.Fc 37.Ft int 38.Fo nftw 39.Fa "const char *path" 40.Fa "int \*[lp]*fn\*[rp]\*[lp]const char *, const struct stat *, int, struct FTW *\*[rp]" 41.Fa "int maxfds" 42.Fa "int flags" 43.Fc 44.Sh DESCRIPTION 45The 46.Fn ftw 47and 48.Fn nftw 49functions traverse (walk) the directory hierarchy rooted in 50.Fa path . 51For each object in the hierarchy, these functions call the function 52pointed to by 53.Fa fn . 54The 55.Fn ftw 56function passes this function a pointer to a 57.Dv NUL Ns 58-terminated string containing 59the name of the object, a pointer to a 60.Vt stat 61structure corresponding to the 62object, and an integer flag. 63The 64.Fn nftw 65function passes the aforementioned arguments plus a pointer to a 66.Vt FTW 67structure as defined by 68.In ftw.h 69(shown below): 70.Bd -literal 71struct FTW { 72 int base; /* offset of basename into pathname */ 73 int level; /* directory depth relative to starting point */ 74}; 75.Ed 76.Pp 77Possible values for the flag passed to 78.Fa fn 79are: 80.Bl -tag -width ".Dv FTW_DNR" 81.It Dv FTW_F 82A regular file. 83.It Dv FTW_D 84A directory being visited in pre-order. 85.It Dv FTW_DNR 86A directory which cannot be read. 87The directory will not be descended into. 88.It Dv FTW_DP 89A directory being visited in post-order 90.Fn ( nftw 91only). 92.It Dv FTW_NS 93A file for which no 94.Xr stat 2 95information was available. 96The contents of the 97.Vt stat 98structure are undefined. 99.It Dv FTW_SL 100A symbolic link. 101.It Dv FTW_SLN 102A symbolic link with a non-existent target 103.Fn ( nftw 104only). 105.El 106.Pp 107The 108.Fn ftw 109function traverses the tree in pre-order. 110That is, it processes the directory before the directory's contents. 111.Pp 112The 113.Fa maxfds 114argument specifies the maximum number of file descriptors 115to keep open while traversing the tree. 116It has no effect in this implementation. 117.Pp 118The 119.Fn nftw 120function has an additional 121.Fa flags 122argument with the following possible values: 123.Bl -tag -width ".Dv FTW_MOUNT" 124.It Dv FTW_PHYS 125Physical walk, do not follow symbolic links. 126.It Dv FTW_MOUNT 127The walk will not cross a mount point. 128.It FTW_DEPTH 129Process directories in post-order. 130Contents of a directory are visited before the directory itself. 131By default, 132.Fn nftw 133traverses the tree in pre-order. 134.It FTW_CHDIR 135Change to a directory before reading it. 136By default, 137.Fn nftw 138will change its starting directory. 139The current working directory will be restored to its original value before 140.Fn nftw 141returns. 142.El 143.Sh RETURN VALUES 144If the tree was traversed successfully, the 145.Fn ftw 146and 147.Fn nftw 148functions return 0. 149If the function pointed to by 150.Fa fn 151returns a non-zero value, 152.Fn ftw 153and 154.Fn nftw 155will stop processing the tree and return the value from 156.Fa fn . 157Both functions return \-1 if an error is detected. 158.Sh ERRORS 159The 160.Fn ftw 161and 162.Fn nftw 163functions may fail and set 164.Va errno 165for any of the errors specified for the library functions 166.Xr close 2 , 167.Xr open 2 , 168.Xr stat 2 , 169.Xr malloc 3 , 170.Xr opendir 3 171and 172.Xr readdir 3 . 173If the 174.Dv FTW_CHDIR 175flag is set, the 176.Fn nftw 177function may fail and set 178.Va errno 179for any of the errors specified for 180.Xr chdir 2 . 181In addition, either function may fail and set 182.Va errno 183as follows: 184.Bl -tag -width Er 185.It Bq Er EINVAL 186The 187.Fa maxfds 188argument is less than 1. 189.El 190.Sh SEE ALSO 191.Xr chdir 2 , 192.Xr close 2 , 193.Xr open 2 , 194.Xr stat 2 , 195.Xr fts 3 , 196.Xr malloc 3 , 197.Xr opendir 3 , 198.Xr readdir 3 199.Sh STANDARDS 200The 201.Fn ftw 202and 203.Fn nftw 204functions conform to 205.St -p1003.1-2001 . 206.Sh HISTORY 207These functions first appeared in 208.At V.3 . 209Their first 210.Fx 211appearance was in 212.Fx 5.3 . 213They were imported into 214.Dx 2.1 . 215.Sh BUGS 216The 217.Fa maxfds 218argument is currently ignored. 219