When you use one of the original Standard File Package procedures SFPutFile , SFGetFile , SFPPutFile , or SFPGetFile , you pass a reply record of type SFReply .
SFReply =
RECORD
good: Boolean; {TRUE if user did not cancel}
copy: Boolean; {reserved}
fType: OSType; {file type}
vRefNum: Integer; {working directory reference number}
version: Integer; {reserved}
fName: Str63; {filename}
END;
In spite of its name, the vRefNum field does not contain a volume reference number. Instead, it contains a working directory reference number, which encodes both the volume reference number and the parent directory ID of the selected file. You can obtain the volume reference number and directory ID of the file by calling GetWDInfo or PBGetWDInfo . See the chapter "File Manager" in this book for details about working directory reference numbers.