1Filesystem(3) Tcl Library Procedures Filesystem(3)
2______________________________________________________________________________
6
8 Tcl_FSRegister, Tcl_FSUnregister, Tcl_FSData, Tcl_FSMountsChanged,
9 Tcl_FSGetFileSystemForPath, Tcl_FSGetPathType, Tcl_FSCopyFile,
10 Tcl_FSCopyDirectory, Tcl_FSCreateDirectory, Tcl_FSDeleteFile, Tcl_FSRe‐
11 moveDirectory, Tcl_FSRenameFile, Tcl_FSListVolumes, Tcl_FSEvalFile,
12 Tcl_FSEvalFileEx, Tcl_FSLoadFile, Tcl_FSUnloadFile, Tcl_FSMatchInDirec‐
13 tory, Tcl_FSLink, Tcl_FSLstat, Tcl_FSUtime, Tcl_FSFileAttrsGet,
14 Tcl_FSFileAttrsSet, Tcl_FSFileAttrStrings, Tcl_FSStat, Tcl_FSAccess,
15 Tcl_FSOpenFileChannel, Tcl_FSGetCwd, Tcl_FSChdir, Tcl_FSPathSeparator,
16 Tcl_FSJoinPath, Tcl_FSSplitPath, Tcl_FSEqualPaths, Tcl_FSGetNormalized‐
17 Path, Tcl_FSJoinToPath, Tcl_FSConvertToPathType, Tcl_FSGetInternalRep,
18 Tcl_FSGetTranslatedPath, Tcl_FSGetTranslatedStringPath, Tcl_FSNewNa‐
19 tivePath, Tcl_FSGetNativePath, Tcl_FSFileSystemInfo, Tcl_GetAccessTime‐
20 FromStat, Tcl_GetBlockSizeFromStat, Tcl_GetBlocksFromStat,
21 Tcl_GetChangeTimeFromStat, Tcl_GetDeviceTypeFromStat, Tcl_GetFSDevice‐
22 FromStat, Tcl_GetFSInodeFromStat, Tcl_GetGroupIdFromStat,
23 Tcl_GetLinkCountFromStat, Tcl_GetModeFromStat, Tcl_GetModificationTime‐
24 FromStat, Tcl_GetSizeFromStat, Tcl_GetUserIdFromStat, Tcl_AllocStatBuf
25 - procedures to interact with any filesystem
26
28 #include <tcl.h>
29 int
31 Tcl_FSRegister(clientData, fsPtr)
32 int
34 Tcl_FSUnregister(fsPtr)
35 ClientData
37 Tcl_FSData(fsPtr)
38 void
40 Tcl_FSMountsChanged(fsPtr)
41 const Tcl_Filesystem *
43 Tcl_FSGetFileSystemForPath(pathPtr)
44 Tcl_PathType
46 Tcl_FSGetPathType(pathPtr)
47 int
49 Tcl_FSCopyFile(srcPathPtr, destPathPtr)
50 int
52 Tcl_FSCopyDirectory(srcPathPtr, destPathPtr, errorPtr)
53 int
55 Tcl_FSCreateDirectory(pathPtr)
56 int
58 Tcl_FSDeleteFile(pathPtr)
59 int
61 Tcl_FSRemoveDirectory(pathPtr, int recursive, errorPtr)
62 int
64 Tcl_FSRenameFile(srcPathPtr, destPathPtr)
65 Tcl_Obj *
67 Tcl_FSListVolumes(void)
68 int
70 Tcl_FSEvalFileEx(interp, pathPtr, encodingName)
71 int
73 Tcl_FSEvalFile(interp, pathPtr)
74 int
76 Tcl_FSLoadFile(interp, pathPtr, sym1, sym2, proc1Ptr, proc2Ptr,
77 loadHandlePtr, unloadProcPtr)
78 int │
80 Tcl_FSUnloadFile(interp, loadHandle) │
81 int
83 Tcl_FSMatchInDirectory(interp, resultPtr, pathPtr, pattern, types)
84 Tcl_Obj *
86 Tcl_FSLink(linkNamePtr, toPtr, linkAction)
87 int
89 Tcl_FSLstat(pathPtr, statPtr)
90 int
92 Tcl_FSUtime(pathPtr, tval)
93 int
95 Tcl_FSFileAttrsGet(interp, int index, pathPtr, objPtrRef)
96 int
98 Tcl_FSFileAttrsSet(interp, int index, pathPtr, Tcl_Obj *objPtr)
99 const char *const *
101 Tcl_FSFileAttrStrings(pathPtr, objPtrRef)
102 int
104 Tcl_FSStat(pathPtr, statPtr)
105 int
107 Tcl_FSAccess(pathPtr, mode)
108 Tcl_Channel
110 Tcl_FSOpenFileChannel(interp, pathPtr, modeString, permissions)
111 Tcl_Obj *
113 Tcl_FSGetCwd(interp)
114 int
116 Tcl_FSChdir(pathPtr)
117 Tcl_Obj *
119 Tcl_FSPathSeparator(pathPtr)
120 Tcl_Obj *
122 Tcl_FSJoinPath(listObj, elements)
123 Tcl_Obj *
125 Tcl_FSSplitPath(pathPtr, lenPtr)
126 int
128 Tcl_FSEqualPaths(firstPtr, secondPtr)
129 Tcl_Obj *
131 Tcl_FSGetNormalizedPath(interp, pathPtr)
132 Tcl_Obj *
134 Tcl_FSJoinToPath(basePtr, objc, objv)
135 int
137 Tcl_FSConvertToPathType(interp, pathPtr)
138 ClientData
140 Tcl_FSGetInternalRep(pathPtr, fsPtr)
141 Tcl_Obj *
143 Tcl_FSGetTranslatedPath(interp, pathPtr)
144 const char *
146 Tcl_FSGetTranslatedStringPath(interp, pathPtr)
147 Tcl_Obj *
149 Tcl_FSNewNativePath(fsPtr, clientData)
150 const void *
152 Tcl_FSGetNativePath(pathPtr)
153 Tcl_Obj *
155 Tcl_FSFileSystemInfo(pathPtr)
156 Tcl_StatBuf *
158 Tcl_AllocStatBuf()
159 Tcl_WideInt │
161 Tcl_GetAccessTimeFromStat(statPtr) │
162 unsigned │
164 Tcl_GetBlockSizeFromStat(statPtr) │
165 Tcl_WideUInt │
167 Tcl_GetBlocksFromStat(statPtr) │
168 Tcl_WideInt │
170 Tcl_GetChangeTimeFromStat(statPtr) │
171 int │
173 Tcl_GetDeviceTypeFromStat(statPtr) │
174 unsigned │
176 Tcl_GetFSDeviceFromStat(statPtr) │
177 unsigned │
179 Tcl_GetFSInodeFromStat(statPtr) │
180 int │
182 Tcl_GetGroupIdFromStat(statPtr) │
183 int │
185 Tcl_GetLinkCountFromStat(statPtr) │
186 unsigned │
188 Tcl_GetModeFromStat(statPtr) │
189 Tcl_WideInt │
191 Tcl_GetModificationTimeFromStat(statPtr) │
192 Tcl_WideUInt │
194 Tcl_GetSizeFromStat(statPtr) │
195 int │
197 Tcl_GetUserIdFromStat(statPtr) │
198
200 const Tcl_Filesystem *fsPtr (in) Points to a structure con‐
201 taining the addresses of
202 procedures that can be
203 called to perform the vari‐
204 ous filesystem operations.
205 Tcl_Obj *pathPtr (in) The path represented by
207 this value is used for the
208 operation in question. If
209 the value does not already
210 have an internal path rep‐
211 resentation, it will be
212 converted to have one.
213 Tcl_Obj *srcPathPtr (in) As for pathPtr, but used
215 for the source file for a
216 copy or rename operation.
217 Tcl_Obj *destPathPtr (in) As for pathPtr, but used
219 for the destination file‐
220 name for a copy or rename
221 operation.
222 const char *encodingName (in) The encoding of the data
224 stored in the file identi‐
225 fied by pathPtr and to be
226 evaluated.
227 const char *pattern (in) Only files or directories
229 matching this pattern will
230 be returned.
231 Tcl_GlobTypeData *types (in) Only files or directories
233 matching the type descrip‐
234 tions contained in this
235 structure will be returned.
236 This parameter may be NULL.
237 Tcl_Interp *interp (in) Interpreter to use either
239 for results, evaluation, or
240 reporting error messages.
241 ClientData clientData (in) The native description of
243 the path value to create.
244 Tcl_Obj *firstPtr (in) The first of two path val‐
246 ues to compare. The value
247 may be converted to path
248 type.
249 Tcl_Obj *secondPtr (in) The second of two path val‐
251 ues to compare. The value
252 may be converted to path
253 type.
254 Tcl_Obj *listObj (in) The list of path elements
256 to operate on with a join
257 operation.
258 int elements (in) If non-negative, the number
260 of elements in the listObj
261 which should be joined
262 together. If negative, then
263 all elements are joined.
264 Tcl_Obj **errorPtr (out) In the case of an error,
266 filled with a value con‐
267 taining the name of the
268 file which caused an error
269 in the various copy/rename
270 operations.
271 Tcl_Obj **objPtrRef (out) Filled with a value con‐
273 taining the result of the
274 operation.
275 Tcl_Obj *resultPtr (out) Pre-allocated value in
277 which to store (using
278 Tcl_ListObjAppendElement)
279 the list of files or direc‐
280 tories which are success‐
281 fully matched.
282 int mode (in) Mask consisting of one or
284 more of R_OK, W_OK, X_OK
285 and F_OK. R_OK, W_OK and
286 X_OK request checking
287 whether the file exists and
288 has read, write and exe‐
289 cute permissions, respec‐
290 tively. F_OK just requests
291 checking for the existence
292 of the file.
293 Tcl_StatBuf *statPtr (out) The structure that contains
295 the result of a stat or
296 lstat operation.
297 const char *sym1 (in) Name of a procedure to look
299 up in the file's symbol ta‐
300 ble
301 const char *sym2 (in) Name of a procedure to look
303 up in the file's symbol ta‐
304 ble
305 Tcl_PackageInitProc **proc1Ptr (out) Filled with the init func‐
307 tion for this code.
308 Tcl_PackageInitProc **proc2Ptr (out) Filled with the safe-init
310 function for this code.
311 ClientData *clientDataPtr (out) Filled with the clientData
313 value to pass to this
314 code's unload function when
315 it is called.
316 Tcl_LoadHandle *loadHandlePtr (out) Filled with an abstract
318 token representing the
319 loaded file.
320 Tcl_FSUnloadFileProc **unloadProcPtr (out) Filled with the function to
322 use to unload this piece of
323 code.
324 Tcl_LoadHandle loadHandle (in) Handle to the loaded
326 library to be unloaded.
327 utimbuf *tval (in) The access and modification
329 times in this structure are
330 read and used to set those
331 values for a given file.
332 const char *modeString (in) Specifies how the file is
334 to be accessed. May have
335 any of the values allowed
336 for the mode argument to
337 the Tcl open command.
338 int permissions (in) POSIX-style permission
340 flags such as 0644. If a
341 new file is created, these
342 permissions will be set on
343 the created file.
344 int *lenPtr (out) If non-NULL, filled with
346 the number of elements in
347 the split path.
348 Tcl_Obj *basePtr (in) The base path on to which
350 to join the given elements.
351 May be NULL.
352 int objc (in) The number of elements in
354 objv.
355 Tcl_Obj *const objv[] (in) The elements to join to the
357 given base path.
358 Tcl_Obj *linkNamePtr (in) The name of the link to be
360 created or read.
361 Tcl_Obj *toPtr (in) What the link called
363 linkNamePtr should be
364 linked to, or NULL if the
365 symbolic link specified by
366 linkNamePtr is to be read.
367 int linkAction (in) OR-ed combination of flags
369 indicating what kind of
370 link should be created
371 (will be ignored if toPtr
372 is NULL). Valid bits to set
373 are TCL_CREATE_SYM‐
374 BOLIC_LINK and TCL_CRE‐
375 ATE_HARD_LINK. When both
376 flags are set and the
377 underlying filesystem can
378 do either, symbolic links
379 are preferred.
380______________________________________________________________________________
381
383 There are several reasons for calling the Tcl_FS API functions
384 (e.g. Tcl_FSAccess and Tcl_FSStat) rather than calling system level
385 functions like access and stat directly. First, they will work cross-
386 platform, so an extension which calls them should work unmodified on
387 Unix and Windows. Second, the Windows implementation of some of these
388 functions fixes some bugs in the system level calls. Third, these func‐
389 tion calls deal with any “Utf to platform-native” path conversions
390 which may be required (and may cache the results of such conversions
391 for greater efficiency on subsequent calls). Fourth, and perhaps most
392 importantly, all of these functions are “virtual filesystem aware”.
393 Any virtual filesystem (VFS for short) which has been registered
394 (through Tcl_FSRegister) may reroute file access to alternative media
395 or access methods. This means that all of these functions (and there‐
396 fore the corresponding file, glob, pwd, cd, open, etc. Tcl commands)
397 may be operate on “files” which are not native files in the native
398 filesystem. This also means that any Tcl extension which accesses the
399 filesystem (FS for short) through this API is automatically “virtual
400 filesystem aware”. Of course, if an extension accesses the native
401 filesystem directly (through platform-specific APIs, for example), then
402 Tcl cannot intercept such calls.
403 If appropriate VFSes have been registered, the “files” may, to give two
405 examples, be remote (e.g. situated on a remote ftp server) or archived
406 (e.g. lying inside a .zip archive). Such registered filesystems provide
407 a lookup table of functions to implement all or some of the functional‐
408 ity listed here. Finally, the Tcl_FSStat and Tcl_FSLstat calls abstract
409 away from what the “struct stat” buffer is actually declared to be,
410 allowing the same code to be used both on systems with and systems
411 without support for files larger than 2GB in size.
412 The Tcl_FS API is Tcl_Obj-ified and may cache internal representations
414 and other path-related strings (e.g. the current working directory).
415 One side-effect of this is that one must not pass in values with a ref‐
416 erence count of zero to any of these functions. If such calls were han‐
417 dled, they might result in memory leaks (under some circumstances, the
418 filesystem code may wish to retain a reference to the passed in value,
419 and so one must not assume that after any of these calls return, the
420 value still has a reference count of zero - it may have been incre‐
421 mented) or in a direct segmentation fault (or other memory access
422 error) due to the value being freed part way through the complex value
423 manipulation required to ensure that the path is fully normalized and
424 absolute for filesystem determination. The practical lesson to learn
425 from this is that
426 Tcl_Obj *path = Tcl_NewStringObj(...);
428 Tcl_FSWhatever(path);
429 Tcl_DecrRefCount(path);
430 is wrong, and may cause memory errors. The path must have its reference
432 count incremented before passing it in, or decrementing it. For this
433 reason, values with a reference count of zero are considered not to be
434 valid filesystem paths and calling any Tcl_FS API function with such a
435 value will result in no action being taken.
436 FS API FUNCTIONS
438 Tcl_FSCopyFile attempts to copy the file given by srcPathPtr to the
439 path name given by destPathPtr. If the two paths given lie in the same
440 filesystem (according to Tcl_FSGetFileSystemForPath) then that filesys‐
441 tem's “copy file” function is called (if it is non-NULL). Otherwise
442 the function returns -1 and sets the errno global C variable to the
443 “EXDEV” POSIX error code (which signifies a “cross-domain link”).
444 Tcl_FSCopyDirectory attempts to copy the directory given by srcPathPtr
446 to the path name given by destPathPtr. If the two paths given lie in
447 the same filesystem (according to Tcl_FSGetFileSystemForPath) then that
448 filesystem's “copy file” function is called (if it is non-NULL). Oth‐
449 erwise the function returns -1 and sets the errno global C variable to
450 the “EXDEV” POSIX error code (which signifies a “cross-domain link”).
451 Tcl_FSCreateDirectory attempts to create the directory given by pathPtr
453 by calling the owning filesystem's “create directory” function.
454 Tcl_FSDeleteFile attempts to delete the file given by pathPtr by call‐
456 ing the owning filesystem's “delete file” function.
457 Tcl_FSRemoveDirectory attempts to remove the directory given by pathPtr
459 by calling the owning filesystem's “remove directory” function.
460 Tcl_FSRenameFile attempts to rename the file or directory given by src‐
462 PathPtr to the path name given by destPathPtr. If the two paths given
463 lie in the same filesystem (according to Tcl_FSGetFileSystemForPath)
464 then that filesystem's “rename file” function is called (if it is non-
465 NULL). Otherwise the function returns -1 and sets the errno global C
466 variable to the “EXDEV” POSIX error code (which signifies a “cross-
467 domain link”).
468 Tcl_FSListVolumes calls each filesystem which has a non-NULL “list vol‐
470 umes” function and asks them to return their list of root volumes. It
471 accumulates the return values in a list which is returned to the caller
472 (with a reference count of 0).
473 Tcl_FSEvalFileEx reads the file given by pathPtr using the encoding
475 identified by encodingName and evaluates its contents as a Tcl script.
476 It returns the same information as Tcl_EvalObjEx. If encodingName is
477 NULL, the system encoding is used for reading the file contents. If
478 the file could not be read then a Tcl error is returned to describe why
479 the file could not be read. The eofchar for files is “\32” (^Z) for
480 all platforms. If you require a “^Z” in code for string comparison,
481 you can use “\032” or “\u001a”, which will be safely substituted by the
482 Tcl interpreter into “^Z”. Tcl_FSEvalFile is a simpler version of
483 Tcl_FSEvalFileEx that always uses the system encoding when reading the
484 file.
485 Tcl_FSLoadFile dynamically loads a binary code file into memory and
487 returns the addresses of two procedures within that file, if they are
488 defined. The appropriate function for the filesystem to which pathPtr
489 belongs will be called. If that filesystem does not implement this
490 function (most virtual filesystems will not, because of OS limitations
491 in dynamically loading binary code), Tcl will attempt to copy the file
492 to a temporary directory and load that temporary file. Tcl_FSUnload‐ │
493 File reverses the operation, asking for the library indicated by the │
494 loadHandle to be removed from the process. Note that, unlike with the │
495 unload command, this does not give the library any opportunity to clean │
496 up.
497 Both the above functions return a standard Tcl completion code. If an
499 error occurs, an error message is left in the interp's result.
500 The token provided via the variable indicated by loadHandlePtr may be │
502 used with Tcl_FindSymbol.
503 Tcl_FSMatchInDirectory is used by the globbing code to search a direc‐
505 tory for all files which match a given pattern. The appropriate func‐
506 tion for the filesystem to which pathPtr belongs will be called.
507 The return value is a standard Tcl result indicating whether an error
509 occurred in globbing. Error messages are placed in interp (unless
510 interp is NULL, which is allowed), but good results are placed in the
511 resultPtr given.
512 Note that the glob code implements recursive patterns internally, so
514 this function will only ever be passed simple patterns, which can be
515 matched using the logic of string match. To handle recursion, Tcl will
516 call this function frequently asking only for directories to be
517 returned. A special case of being called with a NULL pattern indicates
518 that the path needs to be checked only for the correct type.
519 Tcl_FSLink replaces the library version of readlink, and extends it to
521 support the creation of links. The appropriate function for the
522 filesystem to which linkNamePtr belongs will be called.
523 If the toPtr is NULL, a “read link” action is performed. The result is
525 a Tcl_Obj specifying the contents of the symbolic link given by
526 linkNamePtr, or NULL if the link could not be read. The result is owned
527 by the caller, which should call Tcl_DecrRefCount when the result is no
528 longer needed. If the toPtr is not NULL, Tcl should create a link of
529 one of the types passed in in the linkAction flag. This flag is an ORed
530 combination of TCL_CREATE_SYMBOLIC_LINK and TCL_CREATE_HARD_LINK.
531 Where a choice exists (i.e. more than one flag is passed in), the Tcl
532 convention is to prefer symbolic links. When a link is successfully
533 created, the return value should be toPtr (which is therefore already
534 owned by the caller). If unsuccessful, NULL is returned.
535 Tcl_FSLstat fills the Tcl_StatBuf structure statPtr with information
537 about the specified file. You do not need any access rights to the file
538 to get this information but you need search rights to all directories
539 named in the path leading to the file. The Tcl_StatBuf structure
540 includes info regarding device, inode (always 0 on Windows), privilege
541 mode, nlink (always 1 on Windows), user id (always 0 on Windows), group
542 id (always 0 on Windows), rdev (same as device on Windows), size, last
543 access time, last modification time, and last metadata change time.
544 See PORTABLE STAT RESULT API for a description of how to write portable
545 code to allocate and access the Tcl_StatBuf structure.
546 If path exists, Tcl_FSLstat returns 0 and the stat structure is filled
548 with data. Otherwise, -1 is returned, and no stat info is given.
549 Tcl_FSUtime replaces the library version of utime.
551 This returns 0 on success and -1 on error (as per the utime documenta‐
553 tion). If successful, the function will update the “atime” and “mtime”
554 values of the file given.
555 Tcl_FSFileAttrsGet implements read access for the hookable file
557 attributes subcommand. The appropriate function for the filesystem to
558 which pathPtr belongs will be called.
559 If the result is TCL_OK, then a value was placed in objPtrRef, which
561 will only be temporarily valid (unless Tcl_IncrRefCount is called).
562 Tcl_FSFileAttrsSet implements write access for the hookable file
564 attributes subcommand. The appropriate function for the filesystem to
565 which pathPtr belongs will be called.
566 Tcl_FSFileAttrStrings implements part of the hookable file attributes
568 subcommand. The appropriate function for the filesystem to which path‐
569 Ptr belongs will be called.
570 The called procedure may either return an array of strings, or may
572 instead return NULL and place a Tcl list into the given objPtrRef. Tcl
573 will take that list and first increment its reference count before
574 using it. On completion of that use, Tcl will decrement its reference
575 count. Hence if the list should be disposed of by Tcl when done, it
576 should have a reference count of zero, and if the list should not be
577 disposed of, the filesystem should ensure it retains a reference count
578 to the value.
579 Tcl_FSAccess checks whether the process would be allowed to read, write
581 or test for existence of the file (or other filesystem object) whose
582 name is pathname. If pathname is a symbolic link on Unix, then permis‐
583 sions of the file referred by this symbolic link are tested.
584 On success (all requested permissions granted), zero is returned. On
586 error (at least one bit in mode asked for a permission that is denied,
587 or some other error occurred), -1 is returned.
588 Tcl_FSStat fills the Tcl_StatBuf structure statPtr with information
590 about the specified file. You do not need any access rights to the file
591 to get this information but you need search rights to all directories
592 named in the path leading to the file. The Tcl_StatBuf structure
593 includes info regarding device, inode (always 0 on Windows), privilege
594 mode, nlink (always 1 on Windows), user id (always 0 on Windows), group
595 id (always 0 on Windows), rdev (same as device on Windows), size, last
596 access time, last modification time, and last metadata change time.
597 See PORTABLE STAT RESULT API for a description of how to write portable
598 code to allocate and access the Tcl_StatBuf structure.
599 If path exists, Tcl_FSStat returns 0 and the stat structure is filled
601 with data. Otherwise, -1 is returned, and no stat info is given.
602 Tcl_FSOpenFileChannel opens a file specified by pathPtr and returns a
604 channel handle that can be used to perform input and output on the
605 file. This API is modeled after the fopen procedure of the Unix stan‐
606 dard I/O library. The syntax and meaning of all arguments is similar
607 to those given in the Tcl open command when opening a file. If an
608 error occurs while opening the channel, Tcl_FSOpenFileChannel returns
609 NULL and records a POSIX error code that can be retrieved with
610 Tcl_GetErrno. In addition, if interp is non-NULL, Tcl_FSOpenFileChan‐
611 nel leaves an error message in interp's result after any error.
612 The newly created channel is not registered in the supplied inter‐
614 preter; to register it, use Tcl_RegisterChannel. If one of the stan‐
615 dard channels, stdin, stdout or stderr was previously closed, the act
616 of creating the new channel also assigns it as a replacement for the
617 standard channel.
618 Tcl_FSGetCwd replaces the library version of getcwd.
620 It returns the Tcl library's current working directory. This may be
622 different to the native platform's working directory, which happens
623 when the current working directory is not in the native filesystem.
624 The result is a pointer to a Tcl_Obj specifying the current directory,
626 or NULL if the current directory could not be determined. If NULL is
627 returned, an error message is left in the interp's result.
628 The result already has its reference count incremented for the caller.
630 When it is no longer needed, that reference count should be decre‐
631 mented. This is needed for thread-safety purposes, to allow multiple
632 threads to access this and related functions, while ensuring the
633 results are always valid.
634 Tcl_FSChdir replaces the library version of chdir. The path is normal‐
636 ized and then passed to the filesystem which claims it. If that
637 filesystem does not implement this function, Tcl will fallback to a
638 combination of stat and access to check whether the directory exists
639 and has appropriate permissions.
640 For results, see chdir documentation. If successful, we keep a record
642 of the successful path in cwdPathPtr for subsequent calls to
643 Tcl_FSGetCwd.
644 Tcl_FSPathSeparator returns the separator character to be used for most
646 specific element of the path specified by pathPtr (i.e. the last part
647 of the path).
648 The separator is returned as a Tcl_Obj containing a string of length 1.
650 If the path is invalid, NULL is returned.
651 Tcl_FSJoinPath takes the given Tcl_Obj, which must be a valid list
653 (which is allowed to have a reference count of zero), and returns the
654 path value given by considering the first elements elements as valid
655 path segments (each path segment may be a complete path, a partial path
656 or just a single possible directory or file name). If any path segment
657 is actually an absolute path, then all prior path segments are dis‐
658 carded. If elements is less than 0, we use the entire list.
659 It is possible that the returned value is actually an element of the
661 given list, so the caller should be careful to increment the reference
662 count of the result before freeing the list.
663 The returned value, typically with a reference count of zero (but it
665 could be shared under some conditions), contains the joined path. The
666 caller must add a reference count to the value before using it. In par‐
667 ticular, the returned value could be an element of the given list, so
668 freeing the list might free the value prematurely if no reference count
669 has been taken. If the number of elements is zero, then the returned
670 value will be an empty-string Tcl_Obj.
671 Tcl_FSSplitPath takes the given Tcl_Obj, which should be a valid path,
673 and returns a Tcl list value containing each segment of that path as an
674 element. It returns a list value with a reference count of zero. If
675 the passed in lenPtr is non-NULL, the variable it points to will be
676 updated to contain the number of elements in the returned list.
677 Tcl_FSEqualPaths tests whether the two paths given represent the same
679 filesystem object. It returns 1 if the paths are equal, and 0 if they
680 are different. If either path is NULL, 0 is always returned.
681 Tcl_FSGetNormalizedPath this important function attempts to extract
683 from the given Tcl_Obj a unique normalized path representation, whose
684 string value can be used as a unique identifier for the file.
685 It returns the normalized path value, owned by Tcl, or NULL if the path
687 was invalid or could otherwise not be successfully converted. Extrac‐
688 tion of absolute, normalized paths is very efficient (because the
689 filesystem operates on these representations internally), although the
690 result when the filesystem contains numerous symbolic links may not be
691 the most user-friendly version of a path. The return value is owned by
692 Tcl and has a lifetime equivalent to that of the pathPtr passed in
693 (unless that is a relative path, in which case the normalized path
694 value may be freed any time the cwd changes) - the caller can of course
695 increment the reference count if it wishes to maintain a copy for
696 longer.
697 Tcl_FSJoinToPath takes the given value, which should usually be a valid
699 path or NULL, and joins onto it the array of paths segments given.
700 Returns a value, typically with reference count of zero (but it could
702 be shared under some conditions), containing the joined path. The call‐
703 er must add a reference count to the value before using it. If any of
704 the values passed into this function (pathPtr or path elements) have a
705 reference count of zero, they will be freed when this function returns.
706 Tcl_FSConvertToPathType tries to convert the given Tcl_Obj to a valid
708 Tcl path type, taking account of the fact that the cwd may have changed
709 even if this value is already supposedly of the correct type. The
710 filename may begin with “~” (to indicate current user's home directory)
711 or “~<user>” (to indicate any user's home directory).
712 If the conversion succeeds (i.e. the value is a valid path in one of
714 the current filesystems), then TCL_OK is returned. Otherwise TCL_ERROR
715 is returned, and an error message may be left in the interpreter.
716 Tcl_FSGetInternalRep extracts the internal representation of a given
718 path value, in the given filesystem. If the path value belongs to a
719 different filesystem, we return NULL. If the internal representation is
720 currently NULL, we attempt to generate it, by calling the filesystem's
721 Tcl_FSCreateInternalRepProc.
722 Returns NULL or a valid internal path representation. This internal
724 representation is cached, so that repeated calls to this function will
725 not require additional conversions.
726 Tcl_FSGetTranslatedPath attempts to extract the translated path from
728 the given Tcl_Obj.
729 If the translation succeeds (i.e. the value is a valid path), then it
731 is returned. Otherwise NULL will be returned, and an error message may
732 be left in the interpreter. A “translated” path is one which contains
733 no “~” or “~user” sequences (these have been expanded to their current
734 representation in the filesystem). The value returned is owned by the
735 caller, which must store it or call Tcl_DecrRefCount to ensure memory
736 is freed. This function is of little practical use, and Tcl_FSGetNor‐
737 malizedPath or Tcl_FSGetNativePath are usually better functions to use
738 for most purposes.
739 Tcl_FSGetTranslatedStringPath does the same as Tcl_FSGetTranslatedPath,
741 but returns a character string or NULL. The string returned is dynami‐
742 cally allocated and owned by the caller, which must store it or call
743 ckfree to ensure it is freed. Again, Tcl_FSGetNormalizedPath or
744 Tcl_FSGetNativePath are usually better functions to use for most pur‐
745 poses.
746 Tcl_FSNewNativePath performs something like the reverse of the usual
748 obj->path->nativerep conversions. If some code retrieves a path in
749 native form (from, e.g. readlink or a native dialog), and that path is
750 to be used at the Tcl level, then calling this function is an efficient
751 way of creating the appropriate path value type.
752 The resulting value is a pure “path” value, which will only receive a
754 UTF-8 string representation if that is required by some Tcl code.
755 Tcl_FSGetNativePath is for use by the Win/Unix native filesystems, so
757 that they can easily retrieve the native (char* or TCHAR*) representa‐
758 tion of a path. This function is a convenience wrapper around
759 Tcl_FSGetInternalRep. It may be desirable in the future to have non-
760 string-based native representations (for example, on MacOSX, a repre‐
761 sentation using a fileSpec of FSRef structure would probably be more
762 efficient). On Windows a full Unicode representation would allow for
763 paths of unlimited length. Currently the representation is simply a
764 character string which may contain either the relative path or a com‐
765 plete, absolute normalized path in the native encoding (complex condi‐
766 tions dictate which of these will be provided, so neither can be relied
767 upon, unless the path is known to be absolute). If you need a native
768 path which must be absolute, then you should ask for the native version
769 of a normalized path. If for some reason a non-absolute, non-normalized
770 version of the path is needed, that must be constructed separately
771 (e.g. using Tcl_FSGetTranslatedPath).
772 The native representation is cached so that repeated calls to this
774 function will not require additional conversions. The return value is
775 owned by Tcl and has a lifetime equivalent to that of the pathPtr
776 passed in (unless that is a relative path, in which case the native
777 representation may be freed any time the cwd changes).
778 Tcl_FSFileSystemInfo returns a list of two elements. The first element
780 is the name of the filesystem (e.g. “native”, “vfs”, “zip”, or
781 “prowrap”, perhaps), and the second is the particular type of the given
782 path within that filesystem (which is filesystem dependent). The second
783 element may be empty if the filesystem does not provide a further cate‐
784 gorization of files.
785 A valid list value is returned, unless the path value is not recog‐
787 nized, when NULL will be returned.
788 Tcl_FSGetFileSystemForPath returns a pointer to the Tcl_Filesystem
790 which accepts this path as valid.
791 If no filesystem will accept the path, NULL is returned.
793 Tcl_FSGetPathType determines whether the given path is relative to the
795 current directory, relative to the current volume, or absolute.
796 It returns one of TCL_PATH_ABSOLUTE, TCL_PATH_RELATIVE, or
798 TCL_PATH_VOLUME_RELATIVE
799 PORTABLE STAT RESULT API
801 Tcl_AllocStatBuf allocates a Tcl_StatBuf on the system heap (which may
802 be deallocated by being passed to ckfree). This allows extensions to
803 invoke Tcl_FSStat and Tcl_FSLstat without being dependent on the size
804 of the buffer. That in turn depends on the flags used to build Tcl.
805 The portable fields of a Tcl_StatBuf may be read using the following │
807 functions, each of which returns the value of the corresponding field │
808 listed in the table below. Note that on some platforms there may be │
809 other fields in the Tcl_StatBuf as it is an alias for a suitable system │
810 structure, but only the portable ones are made available here. See your │
811 system documentation for a full description of these fields. │
812 Access Function Field │
814 Tcl_GetFSDeviceFromStat st_dev │
815 Tcl_GetFSInodeFromStat st_ino │
816 Tcl_GetModeFromStat st_mode │
817 Tcl_GetLinkCountFromStat st_nlink │
818 Tcl_GetUserIdFromStat st_uid │
819 Tcl_GetGroupIdFromStat st_gid │
820 Tcl_GetDeviceTypeFromStat st_rdev │
821 Tcl_GetAccessTimeFromStat st_atime │
822 Tcl_GetModificationTimeFromStat st_mtime │
823 Tcl_GetChangeTimeFromStat st_ctime │
824 Tcl_GetSizeFromStat st_size │
825 Tcl_GetBlocksFromStat st_blocks │
826 Tcl_GetBlockSizeFromStat st_blksize │
827
830 A filesystem provides a Tcl_Filesystem structure that contains pointers
831 to functions that implement the various operations on a filesystem;
832 these operations are invoked as needed by the generic layer, which gen‐
833 erally occurs through the functions listed above.
834 The Tcl_Filesystem structures are manipulated using the following meth‐
836 ods.
837 Tcl_FSRegister takes a pointer to a filesystem structure and an
839 optional piece of data to associated with that filesystem. On calling
840 this function, Tcl will attach the filesystem to the list of known
841 filesystems, and it will become fully functional immediately. Tcl does
842 not check if the same filesystem is registered multiple times (and in
843 general that is not a good thing to do). TCL_OK will be returned.
844 Tcl_FSUnregister removes the given filesystem structure from the list
846 of known filesystems, if it is known, and returns TCL_OK. If the
847 filesystem is not currently registered, TCL_ERROR is returned.
848 Tcl_FSData will return the ClientData associated with the given
850 filesystem, if that filesystem is registered. Otherwise it will return
851 NULL.
852 Tcl_FSMountsChanged is used to inform the Tcl's core that the set of
854 mount points for the given (already registered) filesystem have
855 changed, and that cached file representations may therefore no longer
856 be correct.
857 THE TCL_FILESYSTEM STRUCTURE
859 The Tcl_Filesystem structure contains the following fields:
860 typedef struct Tcl_Filesystem {
862 const char *typeName;
863 int structureLength;
864 Tcl_FSVersion version;
865 Tcl_FSPathInFilesystemProc *pathInFilesystemProc;
866 Tcl_FSDupInternalRepProc *dupInternalRepProc;
867 Tcl_FSFreeInternalRepProc *freeInternalRepProc;
868 Tcl_FSInternalToNormalizedProc *internalToNormalizedProc;
869 Tcl_FSCreateInternalRepProc *createInternalRepProc;
870 Tcl_FSNormalizePathProc *normalizePathProc;
871 Tcl_FSFilesystemPathTypeProc *filesystemPathTypeProc;
872 Tcl_FSFilesystemSeparatorProc *filesystemSeparatorProc;
873 Tcl_FSStatProc *statProc;
874 Tcl_FSAccessProc *accessProc;
875 Tcl_FSOpenFileChannelProc *openFileChannelProc;
876 Tcl_FSMatchInDirectoryProc *matchInDirectoryProc;
877 Tcl_FSUtimeProc *utimeProc;
878 Tcl_FSLinkProc *linkProc;
879 Tcl_FSListVolumesProc *listVolumesProc;
880 Tcl_FSFileAttrStringsProc *fileAttrStringsProc;
881 Tcl_FSFileAttrsGetProc *fileAttrsGetProc;
882 Tcl_FSFileAttrsSetProc *fileAttrsSetProc;
883 Tcl_FSCreateDirectoryProc *createDirectoryProc;
884 Tcl_FSRemoveDirectoryProc *removeDirectoryProc;
885 Tcl_FSDeleteFileProc *deleteFileProc;
886 Tcl_FSCopyFileProc *copyFileProc;
887 Tcl_FSRenameFileProc *renameFileProc;
888 Tcl_FSCopyDirectoryProc *copyDirectoryProc;
889 Tcl_FSLstatProc *lstatProc;
890 Tcl_FSLoadFileProc *loadFileProc;
891 Tcl_FSGetCwdProc *getCwdProc;
892 Tcl_FSChdirProc *chdirProc;
893 } Tcl_Filesystem;
894 Except for the first three fields in this structure which contain sim‐
896 ple data elements, all entries contain addresses of functions called by
897 the generic filesystem layer to perform the complete range of filesys‐
898 tem related actions.
899 The many functions in this structure are broken down into three cate‐
901 gories: infrastructure functions (almost all of which must be imple‐
902 mented), operational functions (which must be implemented if a complete
903 filesystem is provided), and efficiency functions (which need only be
904 implemented if they can be done so efficiently, or if they have side-
905 effects which are required by the filesystem; Tcl has less efficient
906 emulations it can fall back on). It is important to note that, in the
907 current version of Tcl, most of these fallbacks are only used to handle
908 commands initiated in Tcl, not in C. What this means is, that if a file
909 rename command is issued in Tcl, and the relevant filesystem(s) do not
910 implement their Tcl_FSRenameFileProc, Tcl's core will instead fallback
911 on a combination of other filesystem functions (it will use Tcl_FSCopy‐
912 FileProc followed by Tcl_FSDeleteFileProc, and if Tcl_FSCopyFileProc is
913 not implemented there is a further fallback). However, if a Tcl_FSRe‐
914 nameFileProc command is issued at the C level, no such fallbacks occur.
915 This is true except for the last four entries in the filesystem table
916 (lstat, load, getcwd and chdir) for which fallbacks do in fact occur at
917 the C level.
918 Any functions which take path names in Tcl_Obj form take those names in
920 UTF-8 form. The filesystem infrastructure API is designed to support
921 efficient, cached conversion of these UTF-8 paths to other native rep‐
922 resentations.
923 EXAMPLE FILESYSTEM DEFINITION
925 Here is the filesystem lookup table used by the “vfs” extension which
926 allows filesystem actions to be implemented in Tcl.
927 static Tcl_Filesystem vfsFilesystem = {
929 "tclvfs",
930 sizeof(Tcl_Filesystem),
931 TCL_FILESYSTEM_VERSION_1,
932 &VfsPathInFilesystem,
933 &VfsDupInternalRep,
934 &VfsFreeInternalRep,
935 /* No internal to normalized, since we don't create
936 * any pure 'internal' Tcl_Obj path representations */
937 NULL,
938 /* No create native rep function, since we don't use
939 * it and don't choose to support uses of
940 * Tcl_FSNewNativePath */
941 NULL,
942 /* Normalize path isn't needed - we assume paths only
943 * have one representation */
944 NULL,
945 &VfsFilesystemPathType,
946 &VfsFilesystemSeparator,
947 &VfsStat,
948 &VfsAccess,
949 &VfsOpenFileChannel,
950 &VfsMatchInDirectory,
951 &VfsUtime,
952 /* We choose not to support symbolic links inside our
953 * VFS's */
954 NULL,
955 &VfsListVolumes,
956 &VfsFileAttrStrings,
957 &VfsFileAttrsGet,
958 &VfsFileAttrsSet,
959 &VfsCreateDirectory,
960 &VfsRemoveDirectory,
961 &VfsDeleteFile,
962 /* No copy file; use the core fallback mechanism */
963 NULL,
964 /* No rename file; use the core fallback mechanism */
965 NULL,
966 /* No copy directory; use the core fallback mechanism */
967 NULL,
968 /* Core will use stat for lstat */
969 NULL,
970 /* No load; use the core fallback mechanism */
971 NULL,
972 /* We don't need a getcwd or chdir; the core's own
973 * internal value is suitable */
974 NULL,
975 NULL
976 };
977
979 These fields contain basic information about the filesystem structure
980 and addresses of functions which are used to associate a particular
981 filesystem with a file path, and deal with the internal handling of
982 path representations, for example copying and freeing such representa‐
983 tions.
984 TYPENAME
986 The typeName field contains a null-terminated string that identifies
987 the type of the filesystem implemented, e.g. “native”, “zip” or “vfs”.
988 STRUCTURE LENGTH
990 The structureLength field is generally implemented as
991 sizeof(Tcl_Filesystem), and is there to allow easier binary backwards
992 compatibility if the size of the structure changes in a future Tcl
993 release.
994 VERSION
996 The version field should be set to TCL_FILESYSTEM_VERSION_1.
997 PATHINFILESYSTEMPROC
999 The pathInFilesystemProc field contains the address of a function which
1000 is called to determine whether a given path value belongs to this
1001 filesystem or not. Tcl will only call the rest of the filesystem func‐
1002 tions with a path for which this function has returned TCL_OK. If the
1003 path does not belong, -1 should be returned (the behavior of Tcl for
1004 any other return value is not defined). If TCL_OK is returned, then the
1005 optional clientDataPtr output parameter can be used to return an inter‐
1006 nal (filesystem specific) representation of the path, which will be
1007 cached inside the path value, and may be retrieved efficiently by the
1008 other filesystem functions. Tcl will simultaneously cache the fact that
1009 this path belongs to this filesystem. Such caches are invalidated when
1010 filesystem structures are added or removed from Tcl's internal list of
1011 known filesystems.
1012 typedef int Tcl_FSPathInFilesystemProc(
1014 Tcl_Obj *pathPtr,
1015 ClientData *clientDataPtr);
1016 DUPINTERNALREPPROC
1018 This function makes a copy of a path's internal representation, and is
1019 called when Tcl needs to duplicate a path value. If NULL, Tcl will sim‐
1020 ply not copy the internal representation, which may then need to be
1021 regenerated later.
1022 typedef ClientData Tcl_FSDupInternalRepProc(
1024 ClientData clientData);
1025 FREEINTERNALREPPROC
1027 Free the internal representation. This must be implemented if internal
1028 representations need freeing (i.e. if some memory is allocated when an
1029 internal representation is generated), but may otherwise be NULL.
1030 typedef void Tcl_FSFreeInternalRepProc(
1032 ClientData clientData);
1033 INTERNALTONORMALIZEDPROC
1035 Function to convert internal representation to a normalized path. Only
1036 required if the filesystem creates pure path values with no string/path
1037 representation. The return value is a Tcl value whose string represen‐
1038 tation is the normalized path.
1039 typedef Tcl_Obj *Tcl_FSInternalToNormalizedProc(
1041 ClientData clientData);
1042 CREATEINTERNALREPPROC
1044 Function to take a path value, and calculate an internal representation
1045 for it, and store that native representation in the value. May be NULL
1046 if paths have no internal representation, or if the Tcl_FSPathIn‐
1047 FilesystemProc for this filesystem always immediately creates an inter‐
1048 nal representation for paths it accepts.
1049 typedef ClientData Tcl_FSCreateInternalRepProc(
1051 Tcl_Obj *pathPtr);
1052 NORMALIZEPATHPROC
1054 Function to normalize a path. Should be implemented for all filesystems
1055 which can have multiple string representations for the same path value.
1056 In Tcl, every “path” must have a single unique “normalized” string rep‐
1057 resentation. Depending on the filesystem, there may be more than one
1058 unnormalized string representation which refers to that path (e.g. a
1059 relative path, a path with different character case if the filesystem
1060 is case insensitive, a path contain a reference to a home directory
1061 such as “~”, a path containing symbolic links, etc). If the very last
1062 component in the path is a symbolic link, it should not be converted
1063 into the value it points to (but its case or other aspects should be
1064 made unique). All other path components should be converted from sym‐
1065 bolic links. This one exception is required to agree with Tcl's seman‐
1066 tics with file delete, file rename, file copy operating on symbolic
1067 links. This function may be called with nextCheckpoint either at the
1068 beginning of the path (i.e. zero), at the end of the path, or at any
1069 intermediate file separator in the path. It will never point to any
1070 other arbitrary position in the path. In the last of the three valid
1071 cases, the implementation can assume that the path up to and including
1072 the file separator is known and normalized.
1073 typedef int Tcl_FSNormalizePathProc(
1075 Tcl_Interp *interp,
1076 Tcl_Obj *pathPtr,
1077 int nextCheckpoint);
1078
1080 The fields in this section of the structure contain addresses of func‐
1081 tions which are called to carry out the basic filesystem operations. A
1082 filesystem which expects to be used with the complete standard Tcl com‐
1083 mand set must implement all of these. If some of them are not imple‐
1084 mented, then certain Tcl commands may fail when operating on paths
1085 within that filesystem. However, in some instances this may be desir‐
1086 able (for example, a read-only filesystem should not implement the last
1087 four functions, and a filesystem which does not support symbolic links
1088 need not implement the readlink function, etc. The Tcl core expects
1089 filesystems to behave in this way).
1090 FILESYSTEMPATHTYPEPROC
1092 Function to determine the type of a path in this filesystem. May be
1093 NULL, in which case no type information will be available to users of
1094 the filesystem. The “type” is used only for informational purposes, and
1095 should be returned as the string representation of the Tcl_Obj which is
1096 returned. A typical return value might be “networked”, “zip” or “ftp”.
1097 The Tcl_Obj result is owned by the filesystem and so Tcl will increment
1098 the reference count of that value if it wishes to retain a reference to
1099 it.
1100 typedef Tcl_Obj *Tcl_FSFilesystemPathTypeProc(
1102 Tcl_Obj *pathPtr);
1103 FILESYSTEMSEPARATORPROC
1105 Function to return the separator character(s) for this filesystem.
1106 This need only be implemented if the filesystem wishes to use a differ‐
1107 ent separator than the standard string “/”. Amongst other uses, it is
1108 returned by the file separator command. The return value should be a
1109 value with reference count of zero.
1110 typedef Tcl_Obj *Tcl_FSFilesystemSeparatorProc(
1112 Tcl_Obj *pathPtr);
1113 STATPROC
1115 Function to process a Tcl_FSStat call. Must be implemented for any rea‐
1116 sonable filesystem, since many Tcl level commands depend crucially upon
1117 it (e.g. file atime, file isdirectory, file size, glob).
1118 typedef int Tcl_FSStatProc(
1120 Tcl_Obj *pathPtr,
1121 Tcl_StatBuf *statPtr);
1122 The Tcl_FSStatProc fills the stat structure statPtr with information
1124 about the specified file. You do not need any access rights to the file
1125 to get this information but you need search rights to all directories
1126 named in the path leading to the file. The stat structure includes info
1127 regarding device, inode (always 0 on Windows), privilege mode, nlink
1128 (always 1 on Windows), user id (always 0 on Windows), group id (always
1129 0 on Windows), rdev (same as device on Windows), size, last access
1130 time, last modification time, and last metadata change time.
1131 If the file represented by pathPtr exists, the Tcl_FSStatProc returns 0
1133 and the stat structure is filled with data. Otherwise, -1 is returned,
1134 and no stat info is given.
1135 ACCESSPROC
1137 Function to process a Tcl_FSAccess call. Must be implemented for any
1138 reasonable filesystem, since many Tcl level commands depend crucially
1139 upon it (e.g. file exists, file readable).
1140 typedef int Tcl_FSAccessProc(
1142 Tcl_Obj *pathPtr,
1143 int mode);
1144 The Tcl_FSAccessProc checks whether the process would be allowed to
1146 read, write or test for existence of the file (or other filesystem
1147 object) whose name is in pathPtr. If the pathname refers to a symbolic
1148 link, then the permissions of the file referred by this symbolic link
1149 should be tested.
1150 On success (all requested permissions granted), zero is returned. On
1152 error (at least one bit in mode asked for a permission that is denied,
1153 or some other error occurred), -1 is returned.
1154 OPENFILECHANNELPROC
1156 Function to process a Tcl_FSOpenFileChannel call. Must be implemented
1157 for any reasonable filesystem, since any operations which require open
1158 or accessing a file's contents will use it (e.g. open, encoding, and
1159 many Tk commands).
1160 typedef Tcl_Channel Tcl_FSOpenFileChannelProc(
1162 Tcl_Interp *interp,
1163 Tcl_Obj *pathPtr,
1164 int mode,
1165 int permissions);
1166 The Tcl_FSOpenFileChannelProc opens a file specified by pathPtr and
1168 returns a channel handle that can be used to perform input and output
1169 on the file. This API is modeled after the fopen procedure of the Unix
1170 standard I/O library. The syntax and meaning of all arguments is simi‐
1171 lar to those given in the Tcl open command when opening a file, where
1172 the mode argument is a combination of the POSIX flags O_RDONLY,
1173 O_WRONLY, etc. If an error occurs while opening the channel, the
1174 Tcl_FSOpenFileChannelProc returns NULL and records a POSIX error code
1175 that can be retrieved with Tcl_GetErrno. In addition, if interp is
1176 non-NULL, the Tcl_FSOpenFileChannelProc leaves an error message in
1177 interp's result after any error.
1178 The newly created channel must not be registered in the supplied inter‐
1180 preter by a Tcl_FSOpenFileChannelProc; that task is up to the caller of
1181 Tcl_FSOpenFileChannel (if necessary). If one of the standard channels,
1182 stdin, stdout or stderr was previously closed, the act of creating the
1183 new channel also assigns it as a replacement for the standard channel.
1184 MATCHINDIRECTORYPROC
1186 Function to process a Tcl_FSMatchInDirectory call. If not implemented,
1187 then glob and recursive copy functionality will be lacking in the
1188 filesystem (and this may impact commands like encoding names which use
1189 glob functionality internally).
1190 typedef int Tcl_FSMatchInDirectoryProc(
1192 Tcl_Interp *interp,
1193 Tcl_Obj *resultPtr,
1194 Tcl_Obj *pathPtr,
1195 const char *pattern,
1196 Tcl_GlobTypeData *types);
1197 The function should return all files or directories (or other filesys‐
1199 tem objects) which match the given pattern and accord with the types
1200 specification given. There are two ways in which this function may be
1201 called. If pattern is NULL, then pathPtr is a full path specification
1202 of a single file or directory which should be checked for existence and
1203 correct type. Otherwise, pathPtr is a directory, the contents of which
1204 the function should search for files or directories which have the cor‐
1205 rect type. In either case, pathPtr can be assumed to be both non-NULL
1206 and non-empty. It is not currently documented whether pathPtr will have
1207 a file separator at its end of not, so code should be flexible to both
1208 possibilities.
1209 The return value is a standard Tcl result indicating whether an error
1211 occurred in the matching process. Error messages are placed in interp,
1212 unless interp in NULL in which case no error message need be generated;
1213 on a TCL_OK result, results should be added to the resultPtr value
1214 given (which can be assumed to be a valid unshared Tcl list). The
1215 matches added to resultPtr should include any path prefix given in
1216 pathPtr (this usually means they will be absolute path specifications).
1217 Note that if no matches are found, that simply leads to an empty
1218 result; errors are only signaled for actual file or filesystem problems
1219 which may occur during the matching process.
1220 The Tcl_GlobTypeData structure passed in the types parameter contains
1222 the following fields:
1223 typedef struct Tcl_GlobTypeData {
1225 /* Corresponds to bcdpfls as in 'find -t' */
1226 int type;
1227 /* Corresponds to file permissions */
1228 int perm;
1229 /* Acceptable mac type */
1230 Tcl_Obj *macType;
1231 /* Acceptable mac creator */
1232 Tcl_Obj *macCreator;
1233 } Tcl_GlobTypeData;
1234 There are two specific cases which it is important to handle correctly,
1236 both when types is non-NULL. The two cases are when types->types &
1237 TCL_GLOB_TYPE_DIR or types->types & TCL_GLOB_TYPE_MOUNT are true (and
1238 in particular when the other flags are false). In the first of these
1239 cases, the function must list the contained directories. Tcl uses this
1240 to implement recursive globbing, so it is critical that filesystems
1241 implement directory matching correctly. In the second of these cases,
1242 with TCL_GLOB_TYPE_MOUNT, the filesystem must list the mount points
1243 which lie within the given pathPtr (and in this case, pathPtr need not
1244 lie within the same filesystem - different to all other cases in which
1245 this function is called). Support for this is critical if Tcl is to
1246 have seamless transitions between from one filesystem to another.
1247 UTIMEPROC
1249 Function to process a Tcl_FSUtime call. Required to allow setting (not
1250 reading) of times with file mtime, file atime and the open-r/open-
1251 w/fcopy implementation of file copy.
1252 typedef int Tcl_FSUtimeProc(
1254 Tcl_Obj *pathPtr,
1255 struct utimbuf *tval);
1256 The access and modification times of the file specified by pathPtr
1258 should be changed to the values given in the tval structure.
1259 The return value should be 0 on success and -1 on an error, as with the
1261 system utime.
1262 LINKPROC
1264 Function to process a Tcl_FSLink call. Should be implemented only if
1265 the filesystem supports links, and may otherwise be NULL.
1266 typedef Tcl_Obj *Tcl_FSLinkProc(
1268 Tcl_Obj *linkNamePtr,
1269 Tcl_Obj *toPtr,
1270 int linkAction);
1271 If toPtr is NULL, the function is being asked to read the contents of a
1273 link. The result is a Tcl_Obj specifying the contents of the link given
1274 by linkNamePtr, or NULL if the link could not be read. The result is
1275 owned by the caller (and should therefore have its ref count incre‐
1276 mented before being returned). Any callers should call Tcl_DecrRefCount
1277 on this result when it is no longer needed. If toPtr is not NULL, the
1278 function should attempt to create a link. The result in this case
1279 should be toPtr if the link was successful and NULL otherwise. In this
1280 case the result is not owned by the caller (i.e. no reference count
1281 manipulations on either end are needed). See the documentation for
1282 Tcl_FSLink for the correct interpretation of the linkAction flags.
1283 LISTVOLUMESPROC
1285 Function to list any filesystem volumes added by this filesystem.
1286 Should be implemented only if the filesystem adds volumes at the head
1287 of the filesystem, so that they can be returned by file volumes.
1288 typedef Tcl_Obj *Tcl_FSListVolumesProc(void);
1290 The result should be a list of volumes added by this filesystem, or
1292 NULL (or an empty list) if no volumes are provided. The result value is
1293 considered to be owned by the filesystem (not by Tcl's core), but
1294 should be given a reference count for Tcl. Tcl will use the contents of
1295 the list and then decrement that reference count. This allows filesys‐
1296 tems to choose whether they actually want to retain a “master list” of
1297 volumes or not (if not, they generate the list on the fly and pass it
1298 to Tcl with a reference count of 1 and then forget about the list, if
1299 yes, then they simply increment the reference count of their master
1300 list and pass it to Tcl which will copy the contents and then decrement
1301 the count back to where it was).
1302 Therefore, Tcl considers return values from this proc to be read-only.
1304 FILEATTRSTRINGSPROC
1306 Function to list all attribute strings which are valid for this
1307 filesystem. If not implemented the filesystem will not support the file
1308 attributes command. This allows arbitrary additional information to be
1309 attached to files in the filesystem. If it is not implemented, there is
1310 no need to implement the get and set methods.
1311 typedef const char *const *Tcl_FSFileAttrStringsProc(
1313 Tcl_Obj *pathPtr,
1314 Tcl_Obj **objPtrRef);
1315 The called function may either return an array of strings, or may
1317 instead return NULL and place a Tcl list into the given objPtrRef. Tcl
1318 will take that list and first increment its reference count before
1319 using it. On completion of that use, Tcl will decrement its reference
1320 count. Hence if the list should be disposed of by Tcl when done, it
1321 should have a reference count of zero, and if the list should not be
1322 disposed of, the filesystem should ensure it returns a value with a
1323 reference count of at least one.
1324 FILEATTRSGETPROC
1326 Function to process a Tcl_FSFileAttrsGet call, used by file attributes.
1327 typedef int Tcl_FSFileAttrsGetProc(
1329 Tcl_Interp *interp,
1330 int index,
1331 Tcl_Obj *pathPtr,
1332 Tcl_Obj **objPtrRef);
1333 Returns a standard Tcl return code. The attribute value retrieved,
1335 which corresponds to the index'th element in the list returned by the
1336 Tcl_FSFileAttrStringsProc, is a Tcl_Obj placed in objPtrRef (if TCL_OK
1337 was returned) and is likely to have a reference count of zero. Either
1338 way we must either store it somewhere (e.g. the Tcl result), or
1339 Incr/Decr its reference count to ensure it is properly freed.
1340 FILEATTRSSETPROC
1342 Function to process a Tcl_FSFileAttrsSet call, used by file attributes.
1343 If the filesystem is read-only, there is no need to implement this.
1344 typedef int Tcl_FSFileAttrsSetProc(
1346 Tcl_Interp *interp,
1347 int index,
1348 Tcl_Obj *pathPtr,
1349 Tcl_Obj *objPtr);
1350 The attribute value of the index'th element in the list returned by the
1352 Tcl_FSFileAttrStringsProc should be set to the objPtr given.
1353 CREATEDIRECTORYPROC
1355 Function to process a Tcl_FSCreateDirectory call. Should be implemented
1356 unless the FS is read-only.
1357 typedef int Tcl_FSCreateDirectoryProc(
1359 Tcl_Obj *pathPtr);
1360 The return value is a standard Tcl result indicating whether an error
1362 occurred in the process. If successful, a new directory should have
1363 been added to the filesystem in the location specified by pathPtr.
1364 REMOVEDIRECTORYPROC
1366 Function to process a Tcl_FSRemoveDirectory call. Should be implemented
1367 unless the FS is read-only.
1368 typedef int Tcl_FSRemoveDirectoryProc(
1370 Tcl_Obj *pathPtr,
1371 int recursive,
1372 Tcl_Obj **errorPtr);
1373 The return value is a standard Tcl result indicating whether an error
1375 occurred in the process. If successful, the directory specified by
1376 pathPtr should have been removed from the filesystem. If the recursive
1377 flag is given, then a non-empty directory should be deleted without
1378 error. If this flag is not given, then and the directory is non-empty a
1379 POSIX “EEXIST” error should be signaled. If an error does occur, the
1380 name of the file or directory which caused the error should be placed
1381 in errorPtr.
1382 DELETEFILEPROC
1384 Function to process a Tcl_FSDeleteFile call. Should be implemented
1385 unless the FS is read-only.
1386 typedef int Tcl_FSDeleteFileProc(
1388 Tcl_Obj *pathPtr);
1389 The return value is a standard Tcl result indicating whether an error
1391 occurred in the process. If successful, the file specified by pathPtr
1392 should have been removed from the filesystem. Note that, if the
1393 filesystem supports symbolic links, Tcl will always call this function
1394 and not Tcl_FSRemoveDirectoryProc when needed to delete them (even if
1395 they are symbolic links to directories).
1396
1398 These functions need not be implemented for a particular filesystem
1399 because the core has a fallback implementation available. See each
1400 individual description for the consequences of leaving the field NULL.
1401 LSTATPROC
1403 Function to process a Tcl_FSLstat call. If not implemented, Tcl will
1404 attempt to use the statProc defined above instead. Therefore it need
1405 only be implemented if a filesystem can differentiate between stat and
1406 lstat calls.
1407 typedef int Tcl_FSLstatProc(
1409 Tcl_Obj *pathPtr,
1410 Tcl_StatBuf *statPtr);
1411 The behavior of this function is very similar to that of the
1413 Tcl_FSStatProc defined above, except that if it is applied to a sym‐
1414 bolic link, it returns information about the link, not about the target
1415 file.
1416 COPYFILEPROC
1418 Function to process a Tcl_FSCopyFile call. If not implemented Tcl will
1419 fall back on open-r, open-w and fcopy as a copying mechanism. There‐
1420 fore it need only be implemented if the filesystem can perform that
1421 action more efficiently.
1422 typedef int Tcl_FSCopyFileProc(
1424 Tcl_Obj *srcPathPtr,
1425 Tcl_Obj *destPathPtr);
1426 The return value is a standard Tcl result indicating whether an error
1428 occurred in the copying process. Note that, destPathPtr is the name of
1429 the file which should become the copy of srcPathPtr. It is never the
1430 name of a directory into which srcPathPtr could be copied (i.e. the
1431 function is much simpler than the Tcl level file copy subcommand). Note
1432 that, if the filesystem supports symbolic links, Tcl will always call
1433 this function and not copyDirectoryProc when needed to copy them (even
1434 if they are symbolic links to directories). Finally, if the filesystem
1435 determines it cannot support the file copy action, calling Tcl_SetEr‐
1436 rno(EXDEV) and returning a non-TCL_OK result will tell Tcl to use its
1437 standard fallback mechanisms.
1438 RENAMEFILEPROC
1440 Function to process a Tcl_FSRenameFile call. If not implemented, Tcl
1441 will fall back on a copy and delete mechanism. Therefore it need only
1442 be implemented if the filesystem can perform that action more effi‐
1443 ciently.
1444 typedef int Tcl_FSRenameFileProc(
1446 Tcl_Obj *srcPathPtr,
1447 Tcl_Obj *destPathPtr);
1448 The return value is a standard Tcl result indicating whether an error
1450 occurred in the renaming process. If the filesystem determines it can‐
1451 not support the file rename action, calling Tcl_SetErrno(EXDEV) and
1452 returning a non-TCL_OK result will tell Tcl to use its standard fall‐
1453 back mechanisms.
1454 COPYDIRECTORYPROC
1456 Function to process a Tcl_FSCopyDirectory call. If not implemented, Tcl
1457 will fall back on a recursive file mkdir, file copy mechanism. There‐
1458 fore it need only be implemented if the filesystem can perform that
1459 action more efficiently.
1460 typedef int Tcl_FSCopyDirectoryProc(
1462 Tcl_Obj *srcPathPtr,
1463 Tcl_Obj *destPathPtr,
1464 Tcl_Obj **errorPtr);
1465 The return value is a standard Tcl result indicating whether an error
1467 occurred in the copying process. If an error does occur, the name of
1468 the file or directory which caused the error should be placed in
1469 errorPtr. Note that, destPathPtr is the name of the directory-name
1470 which should become the mirror-image of srcPathPtr. It is not the name
1471 of a directory into which srcPathPtr should be copied (i.e. the func‐
1472 tion is much simpler than the Tcl level file copy subcommand). Finally,
1473 if the filesystem determines it cannot support the directory copy
1474 action, calling Tcl_SetErrno(EXDEV) and returning a non-TCL_OK result
1475 will tell Tcl to use its standard fallback mechanisms.
1476 LOADFILEPROC
1478 Function to process a Tcl_FSLoadFile call. If not implemented, Tcl will
1479 fall back on a copy to native-temp followed by a Tcl_FSLoadFile on that
1480 temporary copy. Therefore it need only be implemented if the filesystem
1481 can load code directly, or it can be implemented simply to return
1482 TCL_ERROR to disable load functionality in this filesystem entirely.
1483 typedef int Tcl_FSLoadFileProc(
1485 Tcl_Interp *interp,
1486 Tcl_Obj *pathPtr,
1487 Tcl_LoadHandle *handlePtr,
1488 Tcl_FSUnloadFileProc *unloadProcPtr);
1489 Returns a standard Tcl completion code. If an error occurs, an error
1491 message is left in the interp's result. The function dynamically loads
1492 a binary code file into memory. On a successful load, the handlePtr
1493 should be filled with a token for the dynamically loaded file, and the
1494 unloadProcPtr should be filled in with the address of a procedure. The
1495 unload procedure will be called with the given Tcl_LoadHandle as its
1496 only parameter when Tcl needs to unload the file. For example, for the
1497 native filesystem, the Tcl_LoadHandle returned is currently a token
1498 which can be used in the private TclpFindSymbol to access functions in
1499 the new code. Each filesystem is free to define the Tcl_LoadHandle as
1500 it requires. Finally, if the filesystem determines it cannot support
1501 the file load action, calling Tcl_SetErrno(EXDEV) and returning a non-
1502 TCL_OK result will tell Tcl to use its standard fallback mechanisms.
1503 UNLOADFILEPROC
1505 Function to unload a previously successfully loaded file. If load was
1506 implemented, then this should also be implemented, if there is any
1507 cleanup action required.
1508 typedef void Tcl_FSUnloadFileProc(
1510 Tcl_LoadHandle loadHandle);
1511 GETCWDPROC
1513 Function to process a Tcl_FSGetCwd call. Most filesystems need not
1514 implement this. It will usually only be called once, if getcwd is
1515 called before chdir. May be NULL.
1516 typedef Tcl_Obj *Tcl_FSGetCwdProc(
1518 Tcl_Interp *interp);
1519 If the filesystem supports a native notion of a current working direc‐
1521 tory (which might perhaps change independent of Tcl), this function
1522 should return that cwd as the result, or NULL if the current directory
1523 could not be determined (e.g. the user does not have appropriate per‐
1524 missions on the cwd directory). If NULL is returned, an error message
1525 is left in the interp's result.
1526 CHDIRPROC
1528 Function to process a Tcl_FSChdir call. If filesystems do not implement
1529 this, it will be emulated by a series of directory access checks. Oth‐
1530 erwise, virtual filesystems which do implement it need only respond
1531 with a positive return result if the pathPtr is a valid, accessible
1532 directory in their filesystem. They need not remember the result, since
1533 that will be automatically remembered for use by Tcl_FSGetCwd. Real
1534 filesystems should carry out the correct action (i.e. call the correct
1535 system chdir API).
1536 typedef int Tcl_FSChdirProc(
1538 Tcl_Obj *pathPtr);
1539 The Tcl_FSChdirProc changes the applications current working directory
1541 to the value specified in pathPtr. The function returns -1 on error or
1542 0 on success.
1543
1545 cd(n), file(n), filename(n), load(n), open(n), pwd(n), source(n),
1546 unload(n)
1547
1549 stat, access, filesystem, vfs, virtual filesystem
1550Tcl 8.4 Filesystem(3)