ASM

DISK I/O

Distinguish file 's alias from folder's alias

I have been using the following (modified from a routine kindly supplied by Rick Brown and possibly others) which works flawlessly and I use it in just about every application that I've written...

The routine allows me to obtain a WDRefNum% of a file, folder or volume, If I know in advance whether I'm resolving a file, folder or volume.

What I need now is to know in advance whether the alias is of a folder or volume.

Is it simply a matter of checking the returned WDRefNum% and

if it is a small negative number (say < 0 and > -100) its a volume
if it is a larger negative number (say < -100) its a folder

or is there a more elegant way of doing this.

'==============================
CLEAR LOCAL
  DIM pBlk.54
  DIM osErr%
LOCAL FN getWDRefNum(dirID&,volRef)
'==============================
  pBlk.ioNamePtr& = 0
  pBlk.ioWDDirID& = dirID&
  pBlk.ioVRefNum = volRef
  pBlk.ioWDProcID& = _"ERIK"
  osErr% = FN OPENWD(@pBlk)
END FN = pBlk.ioVRefNum

'==============================
CLEAR LOCAL
LOCAL FN myGetWDrefNumFromAlias%(theAliasNum%, itemType%)
'===============================
  DIM fSpec;0, fVrefNum%, fParID&, 63 fileName$
  DIM myErr%, WDRefNum%, ParWDRefNum%

  myErr% = FN useAlias(theAliasNum%,fSpec) 'pgpro fn

  LONG IF myErr% = _noErr
    SELECT itemType%
      CASE _isFile
        WDRefNum% = FN getWDRefNum(fParID&,fVrefNum%)
      CASE _isFolder
        PARENTID = fParID&
        ParWDRefNum% = FN getWDRefNum(fParID&,fVrefNum%)
        WDRefNum% = FOLDER(fileName$, ParWDRefNum%)
      CASE _isDisk
        WDRefNum% = FN getWDRefNum(fParID&,fVrefNum%)
    END SELECT
  END IF
END FN = WDRefNum%