PBExchangeFiles Swap the data stored in two files

Use the PBExchangeFiles function to swap the data stored in two files on

the same volume.

pb is a pointer to a FIDParam structure.The relevant fields are as

follows:

Æ ioCompletion ProcPtr 4 12 pointer to completion routine

¨ ioResult short 2 16 result code

Æ ioNamePtr long 4 18 pointer to first filename

Æ ioVRefNum short 2 22 volume specification (volume reference

number, working directory reference number,

drive number, or 0 for default volume)

Æ ioMisc Ptr 4 28 pointer to second filename

Æ ioDestDirID long 4 36 second parent directory ID

€Æ ioSrcDirID long 4 48 first parent directory ID

async is a Boolean value. Use FALSE for normal (synchronous) operation

or TRUE to enqueue the request and resume control immediately. See

Async I/O.

Returns: an operating system Error Code. It will be one of:

noErr (0) No error

nsvErr (-35) Volume not found

ioErr (-36) I/O error

fnfErr (-43) File not found

fLckdErr (-45) File locked

volOfflinErr (-53) Volume is off line

extFSErr (-58) External file system

wrgVolTypeErr (-123) Not an HFS volume

Notes: PBExchangeFiles swaps the data in two files by changing the

information in the volume catalog and, if the files are open, in the file

control blocks. See Using FSSpec Records under the section en titled

Using the File Manager for an illustration of how PBExchangeFiles

changes the catalog entries and file control blocks.

You should use PBExchangeFiles or FSpExchangeFiles to preserve

the file ID when updating an existing file, in case the file is being tracked

through its file ID.

Typically, you use PBExchangeFiles after creating a new file during a

safe save. You identify the names and parent directory IDs of the two files to

be ex changed in the fields ioNamePtr, ioDestNamePtr, ioSrcDirID, and

ioDestDirID. PBExchangeFiles changes the fields in the catalog entries

that record the location of the data and the modification dates. It swaps both

the data forks and the resource forks.

PBExchangeFiles works on either open or closed files. If either file is

open, PBExchangeFiles updates any file control blocks associated with

the file. Exchanging the contents of two files requires essentially the same

access as opening both files for writing.

PBExchangeFiles does not require that file IDs exist for the files being

ex changed.