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28 .\" @(#)directory.3 8.1 (Berkeley) 6/4/93
45 .Nd directory operations
52 .Fn opendir "const char *filename"
54 .Fn fdopendir "int fd"
56 .Fn readdir "DIR *dirp"
58 .Fn readdir_r "DIR *dirp" "struct dirent *entry" "struct dirent **result"
60 .Fn telldir "DIR *dirp"
62 .Fn seekdir "DIR *dirp" "long loc"
64 .Fn rewinddir "DIR *dirp"
66 .Fn closedir "DIR *dirp"
68 .Fn fdclosedir "DIR *dirp"
75 interface is deprecated
76 because it cannot be used correctly unless
84 opens the directory named by
90 returns a pointer to be used to identify the
92 in subsequent operations.
97 cannot be accessed, or if it cannot
99 enough memory to hold the whole thing.
103 function is equivalent to the
105 function except that the directory is specified by a file descriptor
107 rather than by a name.
108 The file offset associated with the file descriptor at the time of the call
109 determines which entries are returned.
111 Upon successful return from
113 the file descriptor is under the control of the system,
114 and if any attempt is made to close the file descriptor,
115 or to modify the state of the associated description other than by means
122 the behavior is undefined.
125 the file descriptor is closed.
128 flag is set on the file descriptor by a successful call to
134 returns a pointer to the next directory entry.
135 The directory entry remains valid until the next call to
140 .Em directory stream .
143 upon reaching the end of the directory or on error.
144 In the event of an error,
146 may be set to any of the values documented for the
153 provides the same functionality as
155 but the caller must provide a directory
157 buffer to store the results in.
158 The buffer must be large enough for a
165 If the read succeeds,
169 upon reaching the end of the directory
176 returns 0 on success or an error number to indicate failure.
181 returns a token representing the current location associated with the named
182 .Em directory stream .
185 are good only for the lifetime of the
189 from which they are derived.
190 If the directory is closed and then
191 reopened, prior values returned by
193 will no longer be valid.
196 are also invalidated by a call to
202 sets the position of the next
205 .Em directory stream .
206 The new position reverts to the one associated with the
210 operation was performed.
215 resets the position of the named
217 to the beginning of the directory.
224 and frees the structure associated with the
227 returning 0 on success.
228 On failure, \-1 is returned and the global variable
230 is set to indicate the error.
234 function is equivalent to the
236 function except that this function returns directory file descriptor instead of
242 returns the integer file descriptor associated with the named
243 .Em directory stream ,
247 Sample code which searches a directory for entry ``name'' is:
248 .Bd -literal -offset indent
253 while ((dp = readdir(dirp)) != NULL) {
254 if (dp->d_namlen == len && strcmp(dp->d_name, name) == 0) {
255 (void)closedir(dirp);
259 (void)closedir(dirp);
278 functions appeared in
292 is likely to be wrong if there are parallel unlinks happening
293 and the directory is larger than one page.
294 There is code to ensure that a
296 to the location given by a
298 immediately before the last
300 will always set the correct location to return the same value as that last
303 This is enough for some applications which want to "push back the last entry read" E.g. Samba.
304 Seeks back to any other location,
305 other than the beginning of the directory,
306 may result in unexpected behaviour if deletes are present.
307 It is hoped that this situation will be resolved with changes to