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. The pointer 82.Dv NULL 83is returned if 84.Fa filename 85cannot be accessed, or if it cannot 86.Xr malloc 3 87enough memory to hold the whole thing. 88.Pp 89The 90.Fn readdir 91function 92returns a pointer to the next directory entry. It returns 93.Dv NULL 94upon reaching the end of the directory or detecting an invalid 95.Fn seekdir 96operation. 97.Pp 98The 99.Fn readdir_r 100function 101provides the same functionality as 102.Fn readdir , 103but the caller must provide a directory 104.Fa entry 105buffer to store the results in. If the read succeeds, 106.Fa result 107is pointed at the 108.Fa entry ; 109upon reaching the end of the directory 110.Fa result 111is set to 112.Dv NULL . 113The 114.Fn readdir_r 115function 116returns 0 on success or an error number to indicate failure. 117.Pp 118The 119.Fn telldir 120function 121returns the current location associated with the named 122.Em directory stream . 123Values returned by 124.Fn telldir 125are good only for the lifetime of the 126.Dv DIR 127pointer, 128.Fa dirp , 129from which they are derived. If the directory is closed and then 130reopened, prior values returned by 131.Fn telldir 132will no longer be valid. 133.Pp 134The 135.Fn seekdir 136function 137sets the position of the next 138.Fn readdir 139operation on the 140.Em directory stream . 141The new position reverts to the one associated with the 142.Em directory stream 143when the 144.Fn telldir 145operation was performed. 146.Pp 147The 148.Fn rewinddir 149function 150resets the position of the named 151.Em directory stream 152to the beginning of the directory. 153.Pp 154The 155.Fn closedir 156function 157closes the named 158.Em directory stream 159and frees the structure associated with the 160.Fa dirp 161pointer, 162returning 0 on success. 163On failure, \-1 is returned and the global variable 164.Va errno 165is set to indicate the error. 166.Pp 167The 168.Fn dirfd 169function 170returns the integer file descriptor associated with the named 171.Em directory stream , 172see 173.Xr open 2 . 174.Pp 175Sample code which searches a directory for entry ``name'' is: 176.Bd -literal -offset indent 177len = strlen(name); 178dirp = opendir("."); 179while ((dp = readdir(dirp)) != NULL) 180 if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { 181 (void)closedir(dirp); 182 return FOUND; 183 } 184(void)closedir(dirp); 185return NOT_FOUND; 186.Ed 187.Sh SEE ALSO 188.Xr close 2 , 189.Xr lseek 2 , 190.Xr open 2 , 191.Xr read 2 , 192.Xr dir 5 193.Sh HISTORY 194The 195.Fn opendir , 196.Fn readdir , 197.Fn telldir , 198.Fn seekdir , 199.Fn rewinddir , 200.Fn closedir , 201and 202.Fn dirfd 203functions appeared in 204.Bx 4.2 . 205