1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 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.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)directory.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt DIRECTORY 3 37.Os 38.Sh NAME 39.Nm opendir , 40.Nm readdir , 41.Nm readdir_r , 42.Nm telldir , 43.Nm seekdir , 44.Nm rewinddir , 45.Nm closedir , 46.Nm dirfd 47.Nd directory operations 48.Sh LIBRARY 49.Lb libc 50.Sh SYNOPSIS 51.In sys/types.h 52.In dirent.h 53.Ft DIR * 54.Fn opendir "const char *filename" 55.Ft struct dirent * 56.Fn readdir "DIR *dirp" 57.Ft int 58.Fn readdir_r "DIR *dirp" "struct dirent *entry" "struct dirent **result" 59.Ft long 60.Fn telldir "DIR *dirp" 61.Ft void 62.Fn seekdir "DIR *dirp" "long loc" 63.Ft void 64.Fn rewinddir "DIR *dirp" 65.Ft int 66.Fn closedir "DIR *dirp" 67.Ft int 68.Fn dirfd "DIR *dirp" 69.Sh DESCRIPTION 70The 71.Fn opendir 72function 73opens the directory named by 74.Fa filename , 75associates a 76.Em directory stream 77with it 78and 79returns a pointer to be used to identify the 80.Em directory stream 81in subsequent operations. 82The pointer 83.Dv NULL 84is returned if 85.Fa filename 86cannot be accessed, or if it cannot 87.Xr malloc 3 88enough memory to hold the whole thing. 89.Pp 90The 91.Fn readdir 92function 93returns a pointer to the next directory entry. 94It returns 95.Dv NULL 96upon reaching the end of the directory or detecting an invalid 97.Fn seekdir 98operation. 99.Pp 100The 101.Fn readdir_r 102function 103provides the same functionality as 104.Fn readdir , 105but the caller must provide a directory 106.Fa entry 107buffer to store the results in. 108If the read succeeds, 109.Fa result 110is pointed at the 111.Fa entry ; 112upon reaching the end of the directory 113.Fa result 114is set to 115.Dv NULL . 116The 117.Fn readdir_r 118function 119returns 0 on success or an error number to indicate failure. 120.Pp 121The 122.Fn telldir 123function 124returns the current location associated with the named 125.Em directory stream . 126Values returned by 127.Fn telldir 128are good only for the lifetime of the 129.Dv DIR 130pointer, 131.Fa dirp , 132from which they are derived. 133If the directory is closed and then 134reopened, prior values returned by 135.Fn telldir 136will no longer be valid. 137.Pp 138The 139.Fn seekdir 140function 141sets the position of the next 142.Fn readdir 143operation on the 144.Em directory stream . 145The new position reverts to the one associated with the 146.Em directory stream 147when the 148.Fn telldir 149operation was performed. 150.Pp 151The 152.Fn rewinddir 153function 154resets the position of the named 155.Em directory stream 156to the beginning of the directory. 157.Pp 158The 159.Fn closedir 160function 161closes the named 162.Em directory stream 163and frees the structure associated with the 164.Fa dirp 165pointer, 166returning 0 on success. 167On failure, \-1 is returned and the global variable 168.Va errno 169is set to indicate the error. 170.Pp 171The 172.Fn dirfd 173function 174returns the integer file descriptor associated with the named 175.Em directory stream , 176see 177.Xr open 2 . 178.Pp 179Sample code which searches a directory for entry ``name'' is: 180.Bd -literal -offset indent 181len = strlen(name); 182dirp = opendir("."); 183while ((dp = readdir(dirp)) != NULL) 184 if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { 185 (void)closedir(dirp); 186 return FOUND; 187 } 188(void)closedir(dirp); 189return NOT_FOUND; 190.Ed 191.Sh SEE ALSO 192.Xr close 2 , 193.Xr lseek 2 , 194.Xr open 2 , 195.Xr read 2 , 196.Xr dir 5 197.Sh HISTORY 198The 199.Fn opendir , 200.Fn readdir , 201.Fn telldir , 202.Fn seekdir , 203.Fn rewinddir , 204.Fn closedir , 205and 206.Fn dirfd 207functions appeared in 208.Bx 4.2 . 209