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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 opens the directory named by
81 returns a pointer to be used to identify the
83 in subsequent operations.
88 cannot be accessed, or if it cannot
90 enough memory to hold the whole thing.
94 function is equivalent to the
96 function except that the directory is specified by a file descriptor
98 rather than by a name.
99 The file offset associated with the file descriptor at the time of the call
100 determines which entries are returned.
102 Upon successful return from
104 the file descriptor is under the control of the system,
105 and if any attempt is made to close the file descriptor,
106 or to modify the state of the associated description other than by means
113 the behavior is undefined.
116 the file descriptor is closed.
119 flag is set on the file descriptor by a successful call to
125 returns a pointer to the next directory entry.
128 upon reaching the end of the directory or on error.
129 In the event of an error,
131 may be set to any of the values documented for the
138 provides the same functionality as
140 but the caller must provide a directory
142 buffer to store the results in.
143 If the read succeeds,
147 upon reaching the end of the directory
154 returns 0 on success or an error number to indicate failure.
159 returns a token representing the current location associated with the named
160 .Em directory stream .
163 are good only for the lifetime of the
167 from which they are derived.
168 If the directory is closed and then
169 reopened, prior values returned by
171 will no longer be valid.
174 are also invalidated by a call to
180 sets the position of the next
183 .Em directory stream .
184 The new position reverts to the one associated with the
188 operation was performed.
193 resets the position of the named
195 to the beginning of the directory.
202 and frees the structure associated with the
205 returning 0 on success.
206 On failure, \-1 is returned and the global variable
208 is set to indicate the error.
212 function is equivalent to the
214 function except that this function returns directory file descriptor instead of
220 returns the integer file descriptor associated with the named
221 .Em directory stream ,
225 Sample code which searches a directory for entry ``name'' is:
226 .Bd -literal -offset indent
231 while ((dp = readdir(dirp)) != NULL) {
232 if (dp->d_namlen == len && strcmp(dp->d_name, name) == 0) {
233 (void)closedir(dirp);
237 (void)closedir(dirp);
256 functions appeared in
270 is likely to be wrong if there are parallel unlinks happening
271 and the directory is larger than one page.
272 There is code to ensure that a
274 to the location given by a
276 immediately before the last
278 will always set the correct location to return the same value as that last
281 This is enough for some applications which want to "push back the last entry read" E.g. Samba.
282 Seeks back to any other location,
283 other than the beginning of the directory,
284 may result in unexpected behaviour if deletes are present.
285 It is hoped that this situation will be resolved with changes to