FN_GETDH()
 Get a directory handle from a drive number
------------------------------------------------------------------------------
 Syntax
 
             fn_GetDH( <nDriveNumber> ) -> <nDirectoryHandle>
 
 Arguments

                 <nDriveNumber> corresponds to an index into the Drive Handle Table
                 (0 to 31) for permanent drives (A..Z) (0..25) and temporary drives
                 ([,\,],,_,') (26..31).  Drive A is 0, drive F is 5, etc.

 Returns

                 <nDirectoryHandle> is the index into the Directory Handle Table.

 Description

                 This call returns the current directory handle for a drive.

 Examples
                        function main( cDrive )
                        
                                local nDirHandle
                        
                                nDirHandle := fn_GetDirHan( asc( upper( cDrive ) ) - 65 )
                        
                                ? fn_DelMap( nDirHandle )
                        
                        return(NIL)


 Source: N:\SRC\FSYS\GETDH.PRG

 Author: David A. Minter