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 BSD 4.2 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.Fd #include <sys/types.h> 52.Fd #include <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 "const 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 98.Fn readdir_r 99provides the same functionality as 100.Fn readdir , 101but the caller must provide a directory 102.Fa entry 103buffer to store the results in. If the read succeeds, 104.Fa result 105is pointed at the 106.Fa entry ; 107upon reaching the end of the directory 108.Fa result 109is set to 110.Dv NULL . 111.Fn readdir_r 112returns 0 on success or an error number to indicate failure. 113.Pp 114The 115.Fn telldir 116function 117returns the current location associated with the named 118.Em directory stream . 119Values returned by 120.Fn telldir 121are good only for the lifetime of the 122.Dv DIR 123pointer, 124.Fa dirp , 125from which they are derived. If the directory is closed and then 126reopened, prior values returned by 127.Fn telldir 128will no longer be valid. 129.Pp 130The 131.Fn seekdir 132function 133sets the position of the next 134.Fn readdir 135operation on the 136.Em directory stream . 137The new position reverts to the one associated with the 138.Em directory stream 139when the 140.Fn telldir 141operation was performed. 142.Pp 143The 144.Fn rewinddir 145function 146resets the position of the named 147.Em directory stream 148to the beginning of the directory. 149.Pp 150The 151.Fn closedir 152function 153closes the named 154.Em directory stream 155and frees the structure associated with the 156.Fa dirp 157pointer, 158returning 0 on success. 159On failure, \-1 is returned and the global variable 160.Va errno 161is set to indicate the error. 162.Pp 163The 164.Fn dirfd 165function 166returns the integer file descriptor associated with the named 167.Em directory stream , 168see 169.Xr open 2 . 170.Pp 171Sample code which searches a directory for entry ``name'' is: 172.Bd -literal -offset indent 173len = strlen(name); 174dirp = opendir("."); 175while ((dp = readdir(dirp)) != NULL) 176 if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { 177 (void)closedir(dirp); 178 return FOUND; 179 } 180(void)closedir(dirp); 181return NOT_FOUND; 182.Ed 183.Sh SEE ALSO 184.Xr close 2 , 185.Xr lseek 2 , 186.Xr open 2 , 187.Xr read 2 , 188.Xr dir 5 189.Sh HISTORY 190The 191.Fn opendir , 192.Fn readdir , 193.Fn telldir , 194.Fn seekdir , 195.Fn rewinddir , 196.Fn closedir , 197and 198.Fn dirfd 199functions appeared in 200.Bx 4.2 . 201