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28 .\" @(#)directory.3 8.1 (Berkeley) 6/4/93
45 .Nd directory operations
51 .Fn opendir "const char *filename"
53 .Fn fdopendir "int fd"
55 .Fn readdir "DIR *dirp"
57 .Fn readdir_r "DIR *dirp" "struct dirent *entry" "struct dirent **result"
59 .Fn telldir "DIR *dirp"
61 .Fn seekdir "DIR *dirp" "long loc"
63 .Fn rewinddir "DIR *dirp"
65 .Fn closedir "DIR *dirp"
67 .Fn fdclosedir "DIR *dirp"
74 interface is deprecated
75 because it cannot be used correctly unless
83 opens the directory named by
89 returns a pointer to be used to identify the
91 in subsequent operations.
96 cannot be accessed, or if it cannot
98 enough memory to hold the whole thing.
102 function is equivalent to the
104 function except that the directory is specified by a file descriptor
106 rather than by a name.
107 The file offset associated with the file descriptor at the time of the call
108 determines which entries are returned.
110 Upon successful return from
112 the file descriptor is under the control of the system,
113 and if any attempt is made to close the file descriptor,
114 or to modify the state of the associated description other than by means
121 the behavior is undefined.
124 the file descriptor is closed.
127 flag is set on the file descriptor by a successful call to
133 returns a pointer to the next directory entry.
134 The directory entry remains valid until the next call to
139 .Em directory stream .
142 upon reaching the end of the directory or on error.
143 In the event of an error,
145 may be set to any of the values documented for the
152 provides the same functionality as
154 but the caller must provide a directory
156 buffer to store the results in.
157 The buffer must be large enough for a
164 If the read succeeds,
168 upon reaching the end of the directory
175 returns 0 on success or an error number to indicate failure.
180 returns a token representing the current location associated with the named
181 .Em directory stream .
184 are good only for the lifetime of the
188 from which they are derived.
189 If the directory is closed and then
190 reopened, prior values returned by
192 will no longer be valid.
195 are also invalidated by a call to
201 sets the position of the next
204 .Em directory stream .
205 The new position reverts to the one associated with the
209 operation was performed.
214 resets the position of the named
216 to the beginning of the directory.
223 and frees the structure associated with the
226 returning 0 on success.
227 On failure, \-1 is returned and the global variable
229 is set to indicate the error.
233 function is equivalent to the
235 function except that this function returns directory file descriptor instead of
241 returns the integer file descriptor associated with the named
242 .Em directory stream ,
246 Sample code which searches a directory for entry ``name'' is:
247 .Bd -literal -offset indent
252 while ((dp = readdir(dirp)) != NULL) {
253 if (dp->d_namlen == len && strcmp(dp->d_name, name) == 0) {
254 (void)closedir(dirp);
258 (void)closedir(dirp);
277 functions appeared in
291 is likely to be wrong if there are parallel unlinks happening
292 and the directory is larger than one page.
293 There is code to ensure that a
295 to the location given by a
297 immediately before the last
299 will always set the correct location to return the same value as that last
302 This is enough for some applications which want to "push back the last entry read" E.g. Samba.
303 Seeks back to any other location,
304 other than the beginning of the directory,
305 may result in unexpected behaviour if deletes are present.
306 It is hoped that this situation will be resolved with changes to