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Inside Macintosh: Files /

Chapter 2 - File Manager / File Manager Reference

File System Specification Routines / Exchanging the Data in Two Files

FSpExchangeFiles

You can use the FSpExchangeFiles function to exchange the data stored in two files on the same volume.

FUNCTION FSpExchangeFiles (source: FSSpec; dest: FSSpec): OSErr;

source

The source file. The contents of this file and its file information are placed in the file specified by the dest parameter.

dest

The destination file. The contents of this file and its file information are placed in the file specified by the source parameter.

DESCRIPTION

The FSpExchangeFiles function swaps the data in two files by changing the information in the volume's catalog and, if the files are open, in the file control
blocks. You should use FSpExchangeFiles when updating an existing file, so
that the file ID remains valid in case the file is being tracked through its file ID.
The FSpExchangeFiles function 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.

The FSpExchangeFiles function works on both open and closed files. If either file is open, FSpExchangeFiles updates any file control blocks associated with the file. Exchanging the contents of two files requires essentially the same access permissions as opening both files for writing.

The files whose data is to be exchanged must both reside on the same volume. If they do not, FSpExchangeFiles returns the result code diffVolErr.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for FSpExchangeFiles are

Trap macro	Selector
_HighLevelHFSDispatch	$000F

RESULT CODES

noErr	0	No error
nsvErr	-35	Volume not found
ioErr	-36	I/O error
fnfErr	-43	File not found
fLckdErr	-45	File is locked
vLckdErr	-46	Volume is locked or read-only
paramErr	-50	Function not supported by volume
volOfflinErr	-53	Volume is offline
wrgVolTypErr	-123	Not an HFS volume
diffVolErr	-1303	Files on different volumes
afpAccessDenied	-5000	User does not have the correct access
afpObjectTypeErr	-5025	Object is a directory, not a file
afpSameObjectErr	-5038	Source and destination files are the same